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# Final Lengthening and vowel length in 25 languages

Ludger Paschen, Susanne Fuchs, Frank Seifart

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Ludger Paschen, Susanne Fuchs, Frank Seifart. Final Lengthening and vowel length in 25 languages. Journal of Phonetics, 2022, 94, pp.101179. 10.1016/j.wocn.2022.101179. hal-04851145

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Journal of Phonetics

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Research Article

# Final Lengthening and vowel length in 25 languages

Ludger Paschen<sup>a,*</sup>, Susanne Fuchs<sup>a</sup>, Frank Seifart<sup>a,b</sup>

<sup>a</sup>Leibniz-Zentrum Allgemeine Sprachwissenschaft, 10117 Berlin, Germany

<sup>b</sup>Institut für deutsche Sprache und Linguistik, Humboldt-Universität zu Berlin, 10099 Berlin, Germany

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## ARTICLE INFO

**Article history:**

Received 23 June 2021

Received in revised form 22 July 2022

Accepted 27 July 2022

Available online 27 August 2022

**Keywords:**

Final lengthening

Phonological quantity

Length contrast

Corpus phonetics

Endangered languages

## ABSTRACT

Lengthening of segments at the end of prosodic domains is commonly considered a universal phenomenon, but language-specific variation has also been reported, specifically in languages with a phonological vowel length contrast. This cross-linguistic study uses spontaneous speech data from the DoReCo corpus as a testbed to investigate Final Lengthening (FL) in a diverse sample of 25 mostly understudied languages, thirteen of which have a phonological vowel length contrast. The duration of vowels was labeled using an automatic aligner, with additional manual corrections of word boundaries upon which refined segment alignments were created. The study reveals that (i) FL is a widespread process across languages; (ii) FL shows a wide variety of manifestations with respect to the degree and scope of lengthening; (iii) there are several significant interactions between phonological length and positional lengthening. These results lend support to theories assuming a phonological nature of Final Lengthening.

© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

## 1. Introduction

Final Lengthening refers to an increase in segmental duration at the right edge of different types of prosodic domains above the word level (e.g. Wightman, Shattuck-Hufnagel, Ostendorf, & Price, 1992; Jun, 1996; Fougeron & Keating, 1997; Fougeron, 2001; Tabain, 2003; Cho, 2016). It is an important cue for prosodic boundaries in speech, along with pauses and other cues such as pitch reset (e.g. d'Imperio & Michelas, 2014; Petrone et al., 2017). Final Lengthening has been found in a broad variety of languages and accordingly plays a prominent role in models of human speech production (Section 1.1). It has also been reported that the domain of lengthening may depend on language-specific prosody (Section 1.2), and that long and short vowels may be affected differently (Section 1.3). Given such language-specific interactions, it is still unclear which aspects of Final Lengthening are to be conceived of as a universal and which aspects are language-specific (e.g. Hockey & Fagyal, 1998; White, Benavides-Varela, & Mády, 2020), considering that phonetic phenomena may be driven by universal principles while still being fine-tuned in language-specific ways and in interaction with other linguistic factors (see Cho & Ladefoged, 1999 & Cho et al.,

Cho, Whalen, & Docherty, 2019 for discussion of variation and universality in voice onset time across languages). The current study aims to shed light on this question by testing a set of hypotheses (Section 1.4) through a systematic analysis of short and long vowels in various positions from a sample of 25 languages.

### 1.1. Universal aspects of Final Lengthening

Final Lengthening (FL) is often assumed to be a universal process of languages (Fletcher, 2010), based on reports of Final Lengthening from numerous languages around the world, and lack of known counterexamples. Final Lengthening has so far been described, among others, in Germanic languages (Kohler, 1983; Horne, Strangert, & Heldner, 1995; Grønnum, 1998; Turk & Shattuck-Hufnagel, 2007; Esposito, 2020; Beltz, Rasskazova, Krivokapić, & Mooshammer, 2022), Slavic languages (Kachkovskaia, Volskaya, & Skrelin, 2013; Wagner, 2014; Jakovljević & Marković, 2020), Romance languages (Fletcher, 1991; Barbosa & Madureira, 1999; White, Payne, & Mattys, 2009; Rao, 2010), and other Indo-European languages (Katsika, 2016; Herringshaw, 2020), as well as Uralic languages (Hockey & Fagyal, 1999; White & Mády, 2008; Nakai, Kunnari, Turk, Suomi, & Ylitalo, 2009; Suomi, Meister, Ylitalo, & Meister, 2013; Plüschke & Harrington, 2013), Afro-

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: paschen@leibniz-zas.de (L. Paschen).</footnote>
Asiatic languages (Berkovits, 1994; De Jong & Zawaydeh, 1999), languages from the Americas (Johnson & Martin, 2001; Gordon & Munro, 2007), Africa (Jokweni, 1995, 1999, 2005, 2007, 2008, 2020), and East Asia (Jun, 1998; Tseng, 2003; Katsuda & Steffman, 2020).

Final Lengthening has also been accounted for in models of speech production. According to the π-gesture theory (Byrd & Saltzman, 2003), lengthening in the vicinity of prosodic boundaries is predicted to be strongest in segments that are immediately adjacent to a boundary, with a diminishing effect as the distance to the boundary increases (Cambier-Langeveld, 1997; Byrd, Krivokapić, & Lee, 2006; Katsika, 2016; Beltz et al., 2022).

Beyond spoken modalities, FL has been found not only in articulatory but also in manual gestures (Weismer & Ingrisano, 1979; Krivokapić, Tiede, & Tyrone, 2017; Fenlon, Cooperrider, Keane, Brentari, & Goldin-Meadow, 2019). There is also evidence for longer tones in final position in speech, music, and bird song (Tierney, Russo, & Patel, 2011). Final Lengthening could be an instantiation of a more general motor property characterized by a deceleration at the end of an action (cf. Klatt, 1976; Berkovits, 1994; Turk & Shattuk-Hufnagel, 2015). The underlying processes of this property are not yet fully understood, but inertia and damping could be involved, as well as extrinsic timing principles associated with the end of a phrase and the beginning of another. Finally, there is a debate about whether Final Lengthening may also be related to speech planning, with more complex upcoming structures requiring slowing down for efficient planning (Krivokapić, 2014).

Thus, empirical findings from different fields of linguistics and interdisciplinary work provide substantial evidence to suggest that Final Lengthening may, on the one hand, be a universal property of languages, and, on the other hand, reflect a general property of movement. The conjecture that the latter alone suffices to explain Final Lengthening has been contested, however (Cho, 2016), and the remainder of this paper will seek to elucidate universal and language-specific aspects of Final Lengthening and their manifestations in vowels of different quantities.

## 1.2. Domains of Final Lengthening

While languages may potentially be uniform in displaying lengthening somewhere in the vicinity of a relevant prosodic boundary, languages differ as to which positions exactly are lengthened and to what degree. By *domain* or *scope* of FL we understand the number of segments or syllables that are affected by lengthening. We use the term *Final Lengthening* to refer to any lengthening within a two-syllable window before a boundary, while we use *final* and *penultimate* to exclusively refer to the ultimate and penultimate position before a boundary. In principle, vowels in stressed or accented syllables may be lengthened in addition to pre-boundary segments, and lengthening in prominent positions can interact with boundary-related lengthening in languages that employ word-level stress. Penultimate stress seems to lead to an earlier onset of lengthening (Wightman et al., 1992) and can extend the domain of FL. But this is not necessarily the case. For example, *Cambier-Langeveld* (1997) showed that the scope

of IP-final lengthening in Dutch is the final rhyme independent of the position of stress, and that stressed syllables further away from a boundary do not participate in FL. For German and Hebrew, it has also been reported that final syllables are still lengthened when the penultimate syllable receives main stress and the final syllable is unstressed (Turk & Shattuck-Hufnagel, 2007). A different pattern is found in many Bantu languages, in which prosodic prominence lies on penultimate rather than final syllables, and this is where lengthening is most often observed (Hyman, 2013).

Previous research has thus demonstrated that stress affects final lengthening regarding which position exactly is lengthened more strongly and how the domain of lengthening has been extended, but lack of FL altogether has not been found so far. While penultimate stress may lead to lengthening in penultimate position, we are not aware of evidence showing that stress placement would override Final Lengthening entirely. Consequently, a typological study like the current one needs to take into account a domain comprising at least the penultimate and final syllables.

## 1.3. Final Lengthening and phonological vowel length

An ideal test case to shed light on the interaction between language-specific grammar and Final Lengthening is phonological vowel length. In some languages, vowel length islexically distinctive (e.g. Finnish *tuuli* 'wind' vs. *tuli* 'fire'), while in other languages it is not. According to the UPSID database (Maddieson & Precoda, 1990), ca. 11% of the world's languages have a phonological vowel length contrast, which in most cases involves a binary distinction between long and short (as in Hungarian, Finnish, Japanese), and in rare cases a ternary distinction between short, long, and overlong (as in Estonian or Dinka, see Krull, 2007; Remijsen & Gilley, 2008, respectively). Systematic differences in Final Lengthening between languages with and without a length contrast, or a heterogenous patterning of short and long vowels, could reveal crucial insights into the extent to which Final Lengthening interacts with language-specific aspects of the phonology.

A number of previous studies have investigated FL in languages with phonological vowel length, see Gordon and Munro (2007) for Chikasaw, Johnson and Martin (2001) for Creek, Remijsen, Ayoker, and Jørgensen (2019) for Shilluk, Remijsen and Gilley (2008) for Dinka, Zellers, Namyalo, and Witzlack-Makarevich (2020) for Ruuli, Lyberg (1977) for Swedish, Jakovljević and Marković (2020) for Serbian and Katsuda and Steffman (2020) for Japanese. Overall, what these studies reveal is that both short and long vowels can in principle be lengthened, but the details seem to be determined by language-specific constraints.

Nakai et al. (2012) report a peculiar interaction of phonological vowel length and FL in Northern Finnish. Final Lengthening affects vowels in the final and penultimate syllable in the following way: if there is at least one long vowel in the final two syllables, this/these long vowel(s) are lengthened; otherwise, the final (short) vowel is lengthened. In other words, long vowels are the preffered target of Final Lengthening and may even cause FL to skip the final syllable in V:CV] words. This implies that Northern Finnish does not seem to have a constraint against phonetically overlong vowels. White and Mády
(2008) investigate lengthening of stressed vowels in Hungarian and find consistent lengthening of long vowels in final and penultimate position but lengthening of short vowels only in final position. Limited lengthening of short vowels has been reported for Estonian, too (Krull, 1997).

Beyond these Uralic languages, different types of interactions have been reported. Jakovljević and Marković (2020) report almost identical degrees of IP-final lengthening for short and long stressed vowels in Serbian. Similarly, Johnson and Martin (2001) found short and long vowels to be lengthened uniformly in Creek. Seo, Kim, Kubozono, and Cho (2019) argue that moraic structure, syllable structure, and pitch accent affect pre-boundary lengthening in different ways in Japanese. Hyman (2013) describes a complex system of penultimate lengthening in Bantu, whereby many (but not all) Bantu languages lengthen penultimate vowels in some (but not all) sentence types, and individual languages may put additional restrictions on which vowel length or combination of vowel lengths may surface in which position.

Another conceivable interaction – not reported so far – could be that languages in which length is contrastive will not use duration as a cue to mark prosodic boundaries, leading to the absence of Final Lengthening. This would be in line with the Functional Load Hypothesis (Berinstein, 1979), which, in its broadest sense, states that if a language uses a certain feature for lexical contrasts, it will not use that feature to mark prosodic categories. This hypothesis has been contested, however; for example, in a study of 140 languages, Lunden, Campbell, Hutchens, and Kalivoda (2017) found no evidence to support the Functional Load Hypothesis, in line with the studies on FL cited above.

Other possible factors that could potentially affect FL include contrast preservation and general markedness. The contrast maximization principle (Flemming, 2002; Stanton, 2018) would predict that languages should avoid lengthening short vowels, at least inasmuch as they should not become confusable with phonologically long vowels. On the other hand, if there is sufficient lengthening of long vowels, short vowels may also have more room to expand without the risk of conflating categories. General markedness (Rice, 2007) would predict that lengthening of phonologically long vowels should be disfavored at least in some languages, as the resulting overlong vowels would be highly marked segments.

## 1.4. Aims and hypotheses

The aim of this paper is twofold. First, we will assess the universality of pre-boundary lengthening (in final and penultimate syllables) across a diverse set of languages. Second, we will scrutinize the relation between phonological vowel length and Final Lengthening. If FL was merely the result of general motor constraints, we should find FL to be realized uniformly in all languages regardless of phonological length. However, if Final Lengthening is a phonological process, it would be expected that language-specific phonological features such as vowel length systematically interact with FL. One could then expect FL to be more restricted in languages with a length contrast in order to preserve length contrasts, or vowels of different quantities to be affected in different ways.

Even though FL has been studied in a fairly wide range of individual languages, studies that have systematically compared languages using the same methodology are limited (see Seifart et al., 2021 for a study on word duration in utterance-final position). Our knowledge on Final Lengthening so far is mostly based on production experiments with speakers from a limited set of languages. The advantage of such a methodology is that various factors affecting FL can be controlled for. However, speech material in these studies is typically read and generalizations do not easily extend to spontaneous speech. In contrast, this paper presents findings from a study on spontaneous speech in a diverse set of 25 languages. The same methodology is applied in terms of data preparation, extraction of the relevant data points and statistical analysis.

In our study, we test the two hypotheses in (1) and (2). H1 is informed by the existing body of literature on Final Lengthening, and seeks to provide cross-linguistic evidence that the effect of FL is detectable in a sample of spontaneous speech from diverse languages analyzed within a uniform methodological framework. H2 tests the phonological nature of FL, which would predict interactions with phonological length to be possible.

(1) Hypothesis 1: Final Lengthening is attested in natural speech from a world-wide sample of 25 languages.

(2) Hypothesis 2: Phonological vowel length interacts with Final Lengthening.

In a first step, these two hypotheses are tested using subsets of the data. For H1, we consider all short vowels from the entire sample of 25 languages. H2 is tested on long and short vowels in 10 languages that have a vowel length contrast in all positions. In a second step, we take a closer look at each of the 25 languages and discuss the degree and scope of Final Lengthening in light of their phonological systems. This part is rather exploratory, because we have no language-specific hypotheses. Due to the richness of phonological systems in our sample (see Appendix A), a closer inspection of individual languages may offer valuable insights into potential excitatory and inhibitory factors affecting the exact manifestation of Final Lengthening in a given language.

# 2. Methodology

## 2.1. Data preparation in DoReCo

All data used in this study come from the DoReCo (“Language Documentation Reference Corpus”) corpus (Seifart, Paschen, & Stave, 2022).<fnref n="1" /> DoReCo is a recent initiative for building a time-aligned speech corpus of endangered and understudied languages. Language samples contained in DoReCo come from collections of fieldwork recordings that have typically been archived at repositories such as ELAR, TLA, and PARADISEC. What makes DoReCo stand out among other

<footnote n="1">¹ Note that counts and measurements presented in this study are based on the pre-release version DoReCo 0.1, which differs slightly from DoReCo 1.0 published in July 2022. The main difference is that the Gurindji dataset, which was considered for DoReCo at the time of writing, was ultimately not included in DoReCo 1.0. The Gurindji data are archived at TLA, available at https://hdl.handle.net/1839/00-0000-0000-0008-683B-1. All data and scripts used for this study are available at https://osf.io/5pfd3.</footnote>
cross-linguistic corpus initiatives is the thorough and meticulous manual checking of word alignments, labeling of disfluencies, and close communication with corpus creators. All this is targeted at producing the best possible word and segment alignments on the basis of reliable and complete orthographic transcriptions. The workflow for turning audio and annotation files from language documentation collections into a time-aligned corpus is standardized for all languages and consists of the following steps. First, negotiations with corpus creators take place to clarify which data can be used and under which conditions (licenses) data may be shared through DoReCo. Next, the data are pre-processed, which involves taking stock of all files and selecting a suitable sample of ca. 10,000 words with sufficient audio quality and complete transcription. Then, a first round of forced alignment is conducted using the language-independent model of WebMAUS (Schiel, 2004). Apart from the audio and transcription files, running WebMAUS also requires several auxiliary files, most notably mapping tables translating graphemes into X-SAMPA symbols. The steps so far are comparable to the workflow of other large speech corpora, see Babinski et al. (2019) and Chodroff, Golden, and Wilson (2019).

The resulting .TextGrid files are then checked manually for correct alignment at the word level. A number of labels are used to mark disfluent or otherwise problematic speech events such as filled pauses, false starts, code-switching,ideo-phones, singing, backchannels, emphatic prolongation or gen- erally unidentifiable words (e.g. due to overlap or background noise). The start and end times of misaligned words are man- ually corrected, labels are inserted at the appropriate places, and any remaining uncertainties are clarified with the original depositors. This post-processing of the results of the first round of forced alignment is unique to DoReCo and particularly time- consuming. On average, it takes one DoReCo team member 120 h to fully post-process a dataset of 10,000 word tokens.

Inter-annotator agreement (IAA) was measured for the addi-
tion and removal of intervals (such as adding a previously
untranscribed false start, or merging two intervals separated
by a wrongly placed pause), as well as for the amount of over-
lap between matching units. IAA between human annotators
was 92–97% for unit addition/removal and 91–95% for unit
overlap. Overlap between human annotators and the forced
aligner was in the range of 82–86%. These figures testify to
the benefit of the arduous manual post-processing for compar-
ative phonetic studies that rely on precise segment alignments.
For more details on IAA, and on the data processing pipeline in
DoReCo in general, the reader is referred to Paschen et al.
(2020).

After post-processing, a second round of forced alignments
is performed, again using the language-independent model of
WebMAUS with a minimum segment duration of 30 ms. This
time, the manually corrected word boundaries serve as input
to the aligner, and the output are segment alignments within
the manually fixed word boundaries. As a last step, forced
alignments are added for intervals that could not be processed
by WebMAUS; the most common cause are extremely short
words which cannot be aligned obeying a minimum segment
duration of 30 ms. Fig. 1 illustrates a typical annotation unit
in Praat after manual post-processing and the final round of
forced alignment.

2.2. Data selection

Datasets from diverse languages were selected for the cur-
rent study for maximum validity of cross-linguistic generaliza-
tions. The final sample includes 25 languages from 19
linguistic families and all six geographical macro-areas recog-
nized by Glottolog (Hammarström, Forkel, Haspelmath, and
Bank, 2020), and encompasses languages with highly diverse
phonologies (see detailed descriptions for each language in
Appendix A).

The following tables offer basic information on the data con-
sidered in this study. Table 1 gives an overview of the selected
datasets from DoReCo, listing number of recordings, unique
speakers, phones, word tokens and inter-pausal units (IPUs).<fnref n="2" />
While a general requirement for datasets in DoReCo is to con-
tain at least 10,000 (orthographic) words or 30,000 phones,
some datasets were slightly below those thresholds, either
due to data scarcity (as is not uncommon for underdocumented
languages) or because a considerable number of words were
labeled as disfluencies, code-switching etc.

Table 2 presents the genealogical and areal affiliations of the languages analyzed in this study and Table 3 provides information on the status of vowel length in the 25 languages. Twelve languages have no phonological vowel length, while thirteen distinguish short and long vowels.<fnref n="3" /> The latter group can be divided into languages with an unrestricted quantity system and those with a restricted quantity system. Here, *restricted* refers to a phonotactic constraint barring long vowels from occurring in word-final syllables; in our sample, three languages belong to this group: Kamas, Mojeño Trinitario, Ruuli. Another dimension along which languages can be divided is *symmetry*, by which we understand whether or not all vowels have short and long counterparts. Most languages in our sample belonged to the unrestricted symmetrical type. More detailed information on the vowel inventories of each language is provided in A.

Fig. 2 presents a map showing the location of the 25 lan-
guages selected for this study. The colors indicate the three
types of lengthening.

2.3. Data preparation

The relevant data for our study were automatically extracted
from the time-aligned .TextGrid files described in the previous
section and exported into a tabular .tsv format using a
custom-made Python script. Each row represented one seg-
ment and contained entries for the following columns: Lan-
guage, Filename, Segment (the time-aligned sound, e.g. /a/),
Duration (of a given sound), StartTime (of the interval contain-
ing a given sound), SoundClass (vowel, stop, fricative, or
sonorant), Word (the orthographic word containing the sound
in question), LeftContext (the symbol preceding the given
sound, can be another sound, label or pause, “NA” if the given
sound is the first segment in a file), RightContext (the symbol
following the given sound, can be another sound, label or
pause, “NA” if the given sound is the last segment in a file),

<footnote n="2">² “English (Southern England)” refers to a variety of Southern English spoken in Kent, UK.</footnote>

<footnote n="3">³ We assigned English to the former group because even though there are long vowels such as /i/ and /ɔ/; length is not contrastive, and all vowels can be distinguished by quality alone.</footnote>
<figure><img src="image_6.png" /><figcaption>**Fig. 1.** A two-second window showing a .wav file with a spectrogram (on top), oscillogram (middle), and a TextGrid with time alignments from the Evenki dataset (Kazakevich & Klyachko, 2021). The first tier contains orthographic words, including labels such as the foreign material d'a'd'a 'uncle' from Russian, labelled as <<fm>>. Labelled items are not included for our analyses. The fourth tier contains the phone alignments in X-SAMPA. The other tiers are automatically generated by WebMAUS and are not relevant for our analysis. The example translates as "the uncle went behind".</figcaption></figure>

<caption>**Table 1**</caption>

The DoReCo datasets used in this study. The columns indicate number of recorded texts, number of unique speakers, total counts of phones, orthographic word tokens (excluding disfluencies) and inter-pausal units (IPUs).

<table><thead><tr><th>Language</th><th>Texts</th><th>Speakers</th><th>Phones</th><th>Words</th><th>IPUs</th><th>Reference</th></tr></thead><tbody><tr><td>Arapaho</td><td>11</td><td>4</td><td>41,540</td><td>4740</td><td>3055</td><td>Cowell (2021)</td></tr><tr><td>Bainounk Gubéeher</td><td>17</td><td>9</td><td>58,130</td><td>11,456</td><td>4910</td><td>Cobbinah (2021)</td></tr><tr><td>Beja</td><td>58</td><td>5</td><td>77,811</td><td>14,735</td><td>4067</td><td>Vanhove (2021)</td></tr><tr><td>Bora</td><td>9</td><td>6</td><td>50,462</td><td>8372</td><td>2977</td><td>Seifart (2021a)</td></tr><tr><td>Dalabon</td><td>10</td><td>4</td><td>24,617</td><td>3400</td><td>1803</td><td>Ponsonnet (2021)</td></tr><tr><td>Dolgan</td><td>9</td><td>6</td><td>45,855</td><td>8781</td><td>2373</td><td>Däbritz, Kudryakova, Stapert, & Arkhipov (2021)</td></tr><tr><td>English (Southern England)</td><td>2</td><td>2</td><td>26,632</td><td>9005</td><td>1350</td><td>Schiborr (2021)</td></tr><tr><td>Evenki</td><td>36</td><td>23</td><td>54,391</td><td>8318</td><td>4187</td><td>Kazakevich and Klyachko (2021)</td></tr><tr><td>Fanbyak</td><td>26</td><td>10</td><td>35,609</td><td>10,217</td><td>2514</td><td>Franjieh (2021)</td></tr><tr><td>Gurindji</td><td>14</td><td>4</td><td>31,994</td><td>5508</td><td>2670</td><td>Meakins (2021)</td></tr><tr><td>Jejuan</td><td>8</td><td>5</td><td>34,538</td><td>7158</td><td>3095</td><td>Kim (2021)</td></tr><tr><td>Kamas</td><td>26</td><td>1</td><td>49,784</td><td>10,076</td><td>4388</td><td>Klooster et al. (2021)</td></tr><tr><td>Lower Sorbian</td><td>15</td><td>4</td><td>38,148</td><td>10,160</td><td>2082</td><td>Bartels et al. (2021)</td></tr><tr><td>Mojeño Trinitario</td><td>10</td><td>6</td><td>44,959</td><td>7897</td><td>2580</td><td>Rose (2021)</td></tr><tr><td>Movima</td><td>12</td><td>5</td><td>52,617</td><td>10,267</td><td>3715</td><td>Haude (2021)</td></tr><tr><td>Nling</td><td>17</td><td>6</td><td>25,775</td><td>10,262</td><td>3629</td><td>Güldemann et al. (2021)</td></tr><tr><td>Resígaro</td><td>21</td><td>3</td><td>43,251</td><td>8162</td><td>3380</td><td>Seifart (2021b)</td></tr><tr><td>Ruuli</td><td>5</td><td>7</td><td>50,420</td><td>8250</td><td>3647</td><td>Witzlack-Makarevich et al. (2021)</td></tr><tr><td>Sadu</td><td>13</td><td>6</td><td>28,055</td><td>11,755</td><td>1819</td><td>Xu et al. (2021)</td></tr><tr><td>Sanzhi Dargwa</td><td>9</td><td>5</td><td>27,380</td><td>4898</td><td>1222</td><td>Forker (2021)</td></tr><tr><td>Svan</td><td>28</td><td>9</td><td>50,376</td><td>9895</td><td>4332</td><td>Gippert (2021)</td></tr><tr><td>Urum</td><td>132</td><td>30</td><td>58,591</td><td>10,081</td><td>3914</td><td>Skopeteas et al. (2021)</td></tr><tr><td>Vera'a</td><td>8</td><td>7</td><td>45,166</td><td>12,292</td><td>2345</td><td>Schnell (2021)</td></tr><tr><td>Yali</td><td>8</td><td>10</td><td>33,420</td><td>7462</td><td>1880</td><td>Riesberg (2021)</td></tr><tr><td>Yongning Na</td><td>6</td><td>1</td><td>31,850</td><td>7481</td><td>2028</td><td>Michaud (2021)</td></tr></tbody></table>

DistanceNextPause (the number of non-pause segments between a given sound and the next pause), DistanceVowel (the number of vowel segments between a given vowel and the next pause, "NA" if sound is not a vowel), IPULength (length of the present IPU in segments), NextPauseDur (duration of the next pause). In its unfiltered state, this .tsv contained 1,294,346 rows. At the same time, a metadata table was prepared containing information on speakers (unique speaker ID, gender, age) and recordings (genre, recording date, sound quality etc.). The metadata table was merged with the table built from the .TextGrid files.

## 2.4. Statistical analysis

The data in the .tsv table were subsequently subjected to various filters. In an initial step, all non-vowel segments were filtered, leaving 538,719 data points with vowels. Then, vowels with a duration ≤30 ms were excluded, as 30 ms was set as the minimum segment duration for WebMAUS and segments with a duration of 30 ms sometimes represent imprecise "last resort" alignments. Furthermore, we excluded all diphthongs and vowels surrounded by disfluencies and code-switching, as these contexts may induce lengthening for independent
<caption>**Table 2**</caption>

Glottocodes (Hammarström et al., 2020) for languages selected for this study, their genealogical classification in terms of top-level family and genus, i.e. (sub-) families of comparable depth used for diversity sampling in typology (Dryer, 1989), as well as their areal distribution.

<table><caption>**Table 3**</caption><thead><tr><th>Language</th><th>Glottocode</th><th>Family</th><th>Genus</th><th>Macro-area</th></tr></thead><tbody><tr><td>Arapaho</td><td>arap1274</td><td>Algic</td><td>Algonquian</td><td>N. America</td></tr><tr><td>Bainounk Gubéeher</td><td>bain1259</td><td>Atlantic–Congo</td><td>Atlantic</td><td>Africa</td></tr><tr><td>Beja</td><td>beja1238</td><td>Afro-Asiatic</td><td>Cushitic</td><td>Africa</td></tr><tr><td>Bora</td><td>bora1263</td><td>Boran</td><td>Boran</td><td>S. America</td></tr><tr><td>Dalabon</td><td>ngal1292</td><td>Guwinyguan</td><td>Marne</td><td>Australia</td></tr><tr><td>Dolgan</td><td>dolg1241</td><td>Turkic</td><td>N. Siberian Turkic</td><td>Eurasia</td></tr><tr><td>English (Southern England)</td><td>sout3282</td><td>Indo-European</td><td>Germanic</td><td>Eurasia</td></tr><tr><td>Evenki</td><td>even1259</td><td>Tungusic</td><td>Northern Tungusic</td><td>Eurasia</td></tr><tr><td>Fanbyak</td><td>orko1234</td><td>Austronesian</td><td>Oceanic</td><td>Papunesia</td></tr><tr><td>Gurindji</td><td>guri1247</td><td>Pama-Nyungan</td><td>Desert Nyungic</td><td>Australia</td></tr><tr><td>Jejuan</td><td>jeju1234</td><td>Koreanic</td><td>Koreanic</td><td>Eurasia</td></tr><tr><td>Kamas</td><td>kama1351</td><td>Uralic</td><td>Samoyedic</td><td>Eurasia</td></tr><tr><td>Lower Sorbian</td><td>lowe1385</td><td>Indo-European</td><td>Slavic</td><td>Eurasia</td></tr><tr><td>Mojeño Trinitario</td><td>trin1278</td><td>Arawakan</td><td>Southern Maipuran</td><td>S. America</td></tr><tr><td>Movima</td><td>movi1243</td><td>(isolate)</td><td>(isolate)</td><td>S. America</td></tr><tr><td>N||ng</td><td>nngg1234</td><td>Tuu</td><td>IUi</td><td>Africa</td></tr><tr><td>Resígaro</td><td>resi1247</td><td>Arawakan</td><td>Japura-Colombia</td><td>S. America</td></tr><tr><td>Ruuli</td><td>ruuli1235</td><td>Atlantic–Congo</td><td>East Bantu</td><td>Africa</td></tr><tr><td>Sadu</td><td>sadu1234</td><td>Sino-Tibetan</td><td>Lolo-Burmese</td><td>Eurasia</td></tr><tr><td>Sanzhi Dargwa</td><td>sanz1248</td><td>Nakh-Dagestanian</td><td>Dargwic</td><td>Eurasia</td></tr><tr><td>Svan</td><td>svan1243</td><td>Kartvelian</td><td>Kartvelian</td><td>Eurasia</td></tr><tr><td>Urum</td><td>urum1249</td><td>Turkic</td><td>Kipchak</td><td>Eurasia</td></tr><tr><td>Vera'a</td><td>vera1241</td><td>Austronesian</td><td>Oceanic</td><td>Papunesia</td></tr><tr><td>Yali</td><td>apah1238</td><td>Nuclear TNG</td><td>Dani</td><td>Papunesia</td></tr><tr><td>Yongning Na</td><td>yong1270</td><td>Sino-Tibetan</td><td>Na-Qiangic</td><td>Eurasia</td></tr></tbody></table>

Vowel length profiles of the 25 languages used in this study: twelve languages without phonological vowel length, three languages with vowel length restricted to non-final positions, and ten languages with unrestricted vowel length. Numbers in brackets indicate the number of short and, if applicable, long vowels. For more details on the vowel inventories, see Appendix A.

<table><thead><tr><th>No length contrast</th><th>Restricted length contrast</th><th>Unrestricted length contrast</th></tr></thead><tbody><tr><td>Dalabon (6)</td><td>Kamas (3/9)</td><td>Arapaho (4/4)</td></tr><tr><td>English (S. E.) (12)</td><td>Mojeño Trinitario (5/5)</td><td>Bainounk Gubéeher (10/10)</td></tr><tr><td>Gurindji (3)</td><td rowspan="2">Ruuli (5/5)</td><td>Beja (5/5)</td></tr><tr><td>Jejuan (9)</td><td>Bora (6/6)</td></tr><tr><td>Lower Sorbian (5)</td><td></td><td>Dolgan (8/8)</td></tr><tr><td>N||ng (16)</td><td></td><td>Fanbyak (7/7)</td></tr><tr><td>Sadu (11)</td><td></td><td>Movima (5/5)</td></tr><tr><td>Sanzhi Dargwa (7)</td><td></td><td>Resígaro (5/5)</td></tr><tr><td>Urum (9)</td><td></td><td>Evenki (5/6)</td></tr><tr><td>Vera'a (7)</td><td></td><td>Svan (6/7)</td></tr><tr><td>Yali (5)</td><td></td><td></td></tr><tr><td>Yongning Na (11)</td><td></td><td></td></tr></tbody></table>

reasons. Since DoReCo contains spontaneous speech material from natural speech, the data contained a considerable number of outliers. Without outlier removal, the residuals of the model were not always linear. For that reason, outliers larger than 3 standard deviations from the upper bound (calculated separately for each language and for each quantity) were removed. Since vowels with a duration ≤30 ms had already been excluded, we did not set an additional lower bound for outliers. In the remaining data pool, vowels were categorized into one of three position classes. Vowels were classified as *Final* when they occurred in the final syllable before a silent pause.<fnref n="4" /> Vowels were considered *Penultimate* when they occurred in the penultimate syllable before a silent pause. Vowels were counted as *Non-final* when they were located in any other syllable and when they where not preceded by a silent pause (this was done to exclude effects of initial strengthening). All vowels with a SAMPA symbol for length (":") were labeled as long (VV), all other vowels were labeled as short (V). Manual inspection of the data revealed that long vowels with a duration of 50 ms or less were almost exclusively the result of faulty alignments, and for that reason, all VV ≤50 ms were excluded from the analysis.

Various analyses were run using R version 4.0.5 (R Core Team, 2020) within the *RStudio* environment (RStudio Team, 2020). We used the libraries *Ime4* (Bates, Mächler, Bolker, & Walker, 2015) and *ImerTest* (Kuznetsova, Brockhoff, & Christensen, 2017) for running linear mixed effect models and obtaining frequentist statistics and the *ggplot2* package (Wickham, 2011) for graphical visualization.

For all statistical analyses the logarithm of *Duration* was taken as the dependent variable. We tested Hypothesis 1 on a subset of our data containing all non-long vowels from the 25 languages, with *Position* (reference level: *Non-final*; other levels: *Penultimate* and *Final*) as the independent factor. Random-slopes were included for *Position by Language* and *Position by Speaker* as well as random intercepts for *Segment* and *IPULength*. The model is given in (3):

$$ (3) \text{Ime}(\log(\text{Duration}) \sim \text{Position} + (1+\text{Position}|\text{Language}) + (1+\text{Position}|\text{sp}) + (1|\text{IPULength}) + (1|\text{Segment})) $$

For testing Hypothesis 2, the interaction between *Position* and *VowelLength* (reference levels: *Non-final* and *V*) were included as independent factors for the 10 languages with an unrestricted length contrast as well as random slopes for *Position by Language*, *Position by Speaker*, *VowelLength by Language*, *VowelLength by Speaker*, and a random intercept for *Segment*. Including further random intercepts resulted in convergence issues. The model is given in (4):

<footnote n="4">⁴ Silent pauses were identified during manual correction of word boundaries before running the final round of forced alignments. The DoReCo team made a great effort to ensure any interval labelled as a silent pause corresponds to some sort of juncture between two prosodic units rather than being just a gap due to consonantal closure. However, as no lower threshold was used for pause length, there will inevitably be some instances where the pause status of an interval could be debated.</footnote>
<figure><img src="image_7.png" /><figcaption>**Fig. 2.** Location of the 25 languages selected for this study. Green dots indicate languages without V length ("V"), blue dots indicate languages with unrestricted V length ("VV"), and black dots mark languages with restricted V length ("VVr"), i.e. length contrasts limited to non-final positions. This map was created using the `lingtypology` package for R (Moroz, 2017).</figcaption></figure>

(4) lmer(log(Duration)~Position*VowelLength+(1+VowelLength|Language)+(1+VowelLength|Speaker)+(1+Position|Language)+(1+Position|Speaker)+(1|Segment))

In case the interaction *Position*\*VowelLength was significant, we ran further posthoc analyses for contrast comparisons using the `emmeans` package (Lenth et al. 2019) with p-value adjustments using the Tukey method comparing a family of 6 estimates.

For calculating individual language models, the dependent and independent factors were kept as similar as possible to the ones described above, but the random structure had to be adopted on a language-by-language basis. For instance, datasets from two languages had only one speaker each, while others contained several dozen speakers, which is why speaker-specific random slopes could only be included in some cases.

For languages without a vowel length contrast, the dependent and independent log-scaled *Duration* was included as the dependent variable and *Position* (reference level: Non-final; other levels: Penultimate and Final) as the independent factor. To account for speaker and item, speaker-specific random slopes for *Position* and *Segment* or *Position* by *Segment* were included in the model. To account for potential coarticulatory influences and gestural overlap by neighboring sounds, *RightContext* and *LeftContext* were included as random intercepts. In some languages, we further included the intercept for the number of segments per inter-pausal unit *IPULength* as well as the upcoming pause duration *NextPauseDur*, a measure which is considered to be “quantitative proxy for boundary strength” (Andreeva, Möbius, & Whang, 2020). The choice of including these last two intercepts relied on model convergence and on the explained variance. If the explained variance was close to 0, models were run without those intercepts.

Languages with a restricted length contrast (Kamas, Mojeño Trinitario and Ruuli) were subsetted into two datasets, one with V containing all the three positions and one with VV

containing only non-final and penultimate positions. Models were built as for languages without a length contrast.

For languages with a full vowel length contrast, the models included the fixed factor *VowelLength* and *Position* (reference level: Non-final). We first ran models for each of the 10 languages with the two fixed factors as an interaction (*Position*\*VowelLength). If the interaction was not significant (which was the case in Beja, Bora, Evenki, Fanbyak, Resigaro, Svan), additive models between the two factors were calculated. We first took V as the reference level and then we changed the references level of *VowelLength* to VV. Doing so allowed us to obtain all comparisons between different levels we were interested in. We chose random effects similarly as in languages without a phonemic length distinction and furthermore added a speaker-specific random slope for *VowelLength* by *Speaker*.

If the interaction between *Position*\*VowelLength was significant (which was the case in Araphao, Baïnounk Gubëeher, Dolgan, Movima), we ran posthoc analyses with `emmeans`.

For two languages, Kamas and Yongning Na, speaker-specific slopes and speaker-specific intercepts were removed because these datasets contained only one speaker each. In the case of Kamas, it was the last speaker of the now extinct language, and in the case of Yongning Na, the data come from a longitudinal study where the same speaker was recorded over the course of multiple years.

## 3. Results

### 3.1. Global analyses

Our sample for testing Hypothesis 1 included a total of 331,776 vowel tokens from 25 languages and 176 unique speakers. Results shown in Fig. 3 reveal that vowels in non-final position ($\beta$ = 4.33, t = 98.07, p < 0.001***) are shorter than vowels in penultimate ($\beta$ = 0.077, t = 7.29, p < 0.001***) and final position ($\beta$ = 0.212, t = 6.63
<figure><img src="image_8.png" /><figcaption>**Fig. 3.** Boxplots for duration in non-final, penultimate and final positions for non-long vowels, pooled data from 25 languages.</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>**Fig. 4.** Boxplots for duration in non-final, penultimate and final positions for short and long vowels, pooled data from 10 languages with a phonological V/VV contrast (left/red: V, right/blue: VV).</figcaption></figure>

p < 0.001**). The results thus confirm Hypothesis 1: Vowels in the vicinity of the right edge of a prosodic domain (operationalized here as inter-pausal units) are consistently longer than vowels in other positions, and the effect is strongest in the syllable immediately before the boundary.

The sample for testing Hypothesis 2 included a total of 174,436 vowels from 10 languages and 76 unique speakers (see Fig. 4). The findings with non-final, non-long vowels as reference levels ($\beta$ = 4.28, t = 82.10, p < 0.001***) provide evidence for a significant difference between the reference level and penultimate position ($\beta$ = 0.098, t = 13.40, p < 0.001***) and final position ($\beta$ = 0.12, t = 3.68, p = 0.005**). Vowels in these positions are significantly longer than in the non-final position. As expected, VV segments were longer than V segments ($\beta$ = 0.47, t = 5.66, p < 0.001**). Furthermore, models revealed an interaction between *VowelLength* and *Position* confirming Hypothesis 2.

Posthoc analyses for H2 are shown in Table 4. Phonologically short vowels are lengthened both in penultimate and final position, but duration values in penultimate position do not differ significantly from duration values in final position. Phonologically long vowels are lengthened the most in penultimate position. In the final position, however, we only observe a trend towards longer duration values compared to non-final vowels, but no significant effect.

## 3.2. Languages without a length contrast

The results of the statistical analyses for the twelve languages without a vowel length contrast are presented in Table 5, and boxplots are shown in Fig. 5. All languages in this group showed a significant lengthening effect in the vowel of the final syllable. The degree of lengthening (see column "Ratio") was in the range between 15% (1.15 = 115% duration compared to reference level) for Gurindji up to 75% for Sadu. Languages thus differed substantially in how much vowels in final syllables were lengthened compared to non-final positions. In eight out of the twelve languages, significant lengthening was also observed in the penultimate syllable, but the degree of lengthening never exceeded that of final syllables. Degrees of penultimate lengthening ranged from 11% in English (Southern England) to 19% in Lower Sorbian. This is compatible with the idea of a decreasing effect of FL with greater distance from a boundary.

## 3.3. Languages with a restricted length contrast

Our sample contained three languages in which VV are restricted in their distribution in that they cannot occur in word-final position. Results for this subgroup of languages is presented in Table 6 and in Fig. 6. Two of the three languages (Kamas, Ruuli) showed strongly significant lengthening of long vowels in the penultimate syllable, with average degrees of lengthening at 22% and 40%, respectively, while one language (Mojeño Trinitario) did not show significant lengthening of VV in penultimate position. Short V did not show a uniform behavior, either. No significant lengthening of short vowels was found in any position in Kamas. In Mojeño Trinitario, penultimate short vowels were lengthened to a significant degree, while final short vowels were slightly shorter, albeit without reaching significance. In Ruuli, short vowels were lengthened in both penultimate and final position. As far as short vowels are concerned, our small sample thus reveals three distinct strategies: no lengthening in Kamas, consistent lengthening in Ruuli, and selective lengthening in penultimate position in Mojeño Trinitario. Long vowels were lengthened in penultimate position in Kamas and Ruuli but not in Mojeño Trinitario.

Our results for Ruuli are consistent with similar findings reported in Zellers et al. (2020). Their study investigated vowel duration in the final three syllables of 358 manually labeled intonational phrases. The authors found progressive lengthening for both short and long vowels, and a stable vowel length contrast across all positions. They further found voice quality differences between penultimate and final vowels with decreased jitter in the former and increased jitter in the latter case. The non-modal phonation in final position was interpreted as a complementary cue to finality with respect to duration. Lastly, they also investigated the relationship between prosody and syntax but did not find significant effects of relative boundary strength across various syntactic categories.

## 3.4. Languages with an unrestricted length contrast

For languages with an unrestricted vowel length contrast, we found notable variation with respect to the scope and degree of lengthening (see Table 7 and Figs. 7 and 8). It is possible to recognize three main patterns. The first pattern is across-the-board lengthening of vowels in final and penultimate position (Fanbyak, Svan). The second pattern involves
<caption>**Table 4**</caption>

Table summarizing Posthoc analysis, p-values were adjusted using the Tukey method comparing a family of 6 estimates. Columns correspond to Categories tested, Estimate (β), Standard error (Std. E.), z-ratio, p-value, and Significance codes (p < 0.05 = *, p < 0.01 = **, p < 0.001 = ***)

<table><caption>**Table 5**</caption><thead><tr><th>Categories</th><th>β</th><th>Std. E.</th><th>z-value</th><th>p-value</th><th>Sign.</th></tr></thead><tbody><tr><td>(Non-final V) × Penult V</td><td>-0.0982</td><td>0.00734</td><td>-13.388</td><td>&lt;.0001</td><td>***</td></tr><tr><td>(Non-final V) × Final V</td><td>-0.1198</td><td>0.03259</td><td>-3.677</td><td>0.0032</td><td>**</td></tr><tr><td>(Non-final V) × (Non-final VV)</td><td>-0.4710</td><td>0.08318</td><td>-5.662</td><td>&lt;.0001</td><td>***</td></tr><tr><td>(Non-final V) × Penult VV</td><td>-0.6126</td><td>0.08361</td><td>-7.328</td><td>&lt;.0001</td><td>***</td></tr><tr><td>(Non-final V) × Final VV</td><td>-0.5620</td><td>0.08947</td><td>-6.281</td><td>&lt;.0001</td><td>***</td></tr><tr><td>Penult V × Final V</td><td>-0.0216</td><td>0.02879</td><td>-0.750</td><td>0.9756</td><td>***</td></tr><tr><td>Penult V × Non-final VV</td><td>-0.3728</td><td>0.08348</td><td>-4.465</td><td>0.0001</td><td>***</td></tr><tr><td>Penult V × Penult VV</td><td>-0.5144</td><td>0.08340</td><td>-6.168</td><td>&lt;.0001</td><td>***</td></tr><tr><td>Penult V × Final VV</td><td>-0.4637</td><td>0.08817</td><td>-5.260</td><td>&lt;.0001</td><td>***</td></tr><tr><td>Final V × (Non-final VV)</td><td>-0.3512</td><td>0.08931</td><td>-3.932</td><td>0.0012</td><td>**</td></tr><tr><td>Final V × Penult VV</td><td>-0.4928</td><td>0.08811</td><td>-5.593</td><td>&lt;.0001</td><td>***</td></tr><tr><td>Final V × Final VV</td><td>-0.4422</td><td>0.08344</td><td>-5.299</td><td>&lt;.0001</td><td>***</td></tr><tr><td>(Non-final VV) × Penult VV</td><td>-0.1416</td><td>0.00948</td><td>-14.937</td><td>&lt;.0001</td><td>***</td></tr><tr><td>(Non-final VV) × Final VV</td><td>-0.0910</td><td>0.03327</td><td>-2.734</td><td>0.0686</td><td>***</td></tr><tr><td>Penult VV × Final VV</td><td>0.0507</td><td>0.02990</td><td>1.694</td><td>0.5356</td><td>***</td></tr></tbody></table>

Table summarizing statistics for all languages without a length contrast. Columns show Language (with percentages of removed outliers in brackets), Position (Intercept is Non-final), Number of samples (N), Estimate (β), t-value, p-value, Significance level (p < 0.05 = *, p < 0.01 = **, p < 0.001 = ***) and Ratio (degree of lengthening between different positions) calculated as mean(Penultimate or Final)/mean(Non-final) for Position and mean(VV)/mean(V) for VowelLength (ratios are based on non-log values).

<table><thead><tr><th>Language</th><th>Position</th><th>N</th><th>β</th><th>t-value</th><th>p-value</th><th>Sign.</th><th>Ratio</th></tr></thead><tbody><tr><td rowspan="3">Dalabon<br>(2.26% out)</td><td>Non-final</td><td>5200</td><td>4.39</td><td>65.87</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1219</td><td>0.088</td><td>1.78</td><td>0.13</td><td></td><td>1.09</td></tr><tr><td>Final</td><td>1154</td><td>0.249</td><td>3.44</td><td>0.033</td><td>*</td><td>1.38</td></tr><tr><td rowspan="3">English (S. E.)<br>(1.65% out)</td><td>Non-final</td><td>4576</td><td>4.672</td><td>64.32</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>722</td><td>0.101</td><td>4.52</td><td>&lt;.0001</td><td>***</td><td>1.11</td></tr><tr><td>Final</td><td>779</td><td>0.334</td><td>11.49</td><td>&lt;.0001</td><td>***</td><td>1.39</td></tr><tr><td rowspan="3">Gurindji<br>(2.17% out)</td><td>Non-final</td><td>8444</td><td>4.28</td><td>47.26</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1688</td><td>0.120</td><td>6.05</td><td>0.045</td><td>*</td><td>1.12</td></tr><tr><td>Final</td><td>1674</td><td>0.138</td><td>2.95</td><td>0.026</td><td>*</td><td>1.15</td></tr><tr><td rowspan="3">Jejuan<br>(1.97% out)</td><td>Non-final</td><td>7560</td><td>4.36</td><td>62.09</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1213</td><td>0.076</td><td>2.99</td><td>0.044</td><td>*</td><td>1.12</td></tr><tr><td>Final</td><td>1305</td><td>0.176</td><td>2.42</td><td>0.041</td><td>*</td><td>1.32</td></tr><tr><td rowspan="3">Lower Sorbian<br>(1.47% out)</td><td>Non-final</td><td>9898</td><td>4.66</td><td>52.49</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1828</td><td>0.118</td><td>6.29</td><td>&lt;.0001</td><td>***</td><td>1.19</td></tr><tr><td>Final</td><td>1960</td><td>0.297</td><td>5.36</td><td>&lt;.0001</td><td>***</td><td>1.54</td></tr><tr><td rowspan="3">N||ng<br>(1.40% out)</td><td>Non-final</td><td>6699</td><td>4.711</td><td>59.51</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>2221</td><td>0.094</td><td>3.85</td><td>0.009</td><td>*</td><td>1.18</td></tr><tr><td>Final</td><td>2450</td><td>0.121</td><td>2.19</td><td>0.045</td><td>*</td><td>1.33</td></tr><tr><td rowspan="3">Sadu<br>(1.93% out)</td><td>Non-final</td><td>9950</td><td>4.410</td><td>59.37</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1579</td><td>0.055</td><td>1.73</td><td>0.127</td><td></td><td>0.97</td></tr><tr><td>Final</td><td>1504</td><td>0.615</td><td>5.92</td><td>&lt;.0001</td><td>***</td><td>1.75</td></tr><tr><td rowspan="3">Sanzhi Dargwa<br>(1.83% out)</td><td>Non-final</td><td>6704</td><td>4.408</td><td>43.77</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>815</td><td>0.097</td><td>1.93</td><td>0.146</td><td></td><td>1.14</td></tr><tr><td>Final</td><td>860</td><td>0.344</td><td>4.51</td><td>0.002</td><td>**</td><td>1.44</td></tr><tr><td rowspan="3">Urum<br>(1.56% out)</td><td>Non-final</td><td>14900</td><td>4.439</td><td>155.65</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>2740</td><td>0.096</td><td>9.20</td><td>0.001</td><td>**</td><td>1.10</td></tr><tr><td>Final</td><td>2796</td><td>0.251</td><td>15.78</td><td>&lt;.0001</td><td>***</td><td>1.28</td></tr><tr><td rowspan="3">Vera'a<br>(2.14% out)</td><td>Non-final</td><td>10818</td><td>4.196</td><td>71.41</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1653</td><td>0.123</td><td>2.92</td><td>0.022</td><td>*</td><td>1.15</td></tr><tr><td>Final</td><td>1831</td><td>0.387</td><td>6.38</td><td>&lt;.0001</td><td>***</td><td>1.45</td></tr><tr><td rowspan="3">Yali<br>(2.15% out)</td><td>Non-final</td><td>8459</td><td>4.183</td><td>100.70</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1146</td><td>0.140</td><td>5.04</td><td>0.003</td><td>**</td><td>1.17</td></tr><tr><td>Final</td><td>1258</td><td>0.369</td><td>3.40</td><td>0.006</td><td>**</td><td>1.79</td></tr><tr><td rowspan="3">Yongning Na<br>(2.98% out)</td><td>Non-final</td><td>9687</td><td>4.459</td><td>52.55</td><td>&lt;.0001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1521</td><td>0.004</td><td>0.15</td><td>0.892</td><td></td><td>0.93</td></tr><tr><td>Final</td><td>1750</td><td>0.314</td><td>2.20</td><td>0.034</td><td>*</td><td>1.38</td></tr></tbody></table>

lengthening of vowels in penultimate but not in final position (Beja, Bora, Evenki, Resígaro). The third pattern refers to various complex interactions between VowelLength and Position (Arapaho, Baïnounk Gubëeher, Dolgan, Movima).

The effect of Final Lengthening on short vowels – in those cases where it reached statistical significance – was between

11% in Bora and Svan penultimate syllables and 31% in Svan final syllables. The effect of Final Lengthening on long vowels that reached statistical significance was between 2% in Fanbyak penultimate syllables and 38% in Fanbyak final syllables. The only effect that was stable across all languages with unrestricted length was VowelLength, which means that long vow-
<figure><img src="image_10.png" /><figcaption>Fig. 5. Boxplots for duration in different syllable positions (from left to right: non-final, penultimate, final) for languages without a vowel length contrast.</figcaption></figure>

**Table 6**

Table summarizing statistics for all languages with a restricted length contrast. Columns show Language (with percentages of removed outliers in brackets), Position (Intercept is Non-final), Number of samples (N), Estimate (β), t-value, p-value, Significance level (p < 0.05 = *, p < 0.01 = **, p < 0.001 = ***, and Ratio (degree of lengthening between different positions) calculated as mean(Penultimate or Final)/mean(Non-final) for Position and mean(VV)/mean(V) for VowelLength (ratios are based on non-log values).

<table><thead><tr><th>Language</th><th>Length</th><th>Position</th><th>N</th><th>β</th><th>t-value</th><th>p-value</th><th>Sign.</th><th>Ratio</th></tr></thead><tbody><tr><td rowspan="3">Kamas<br>(1.29% out)</td><td rowspan="3">V</td><td>Non-final</td><td>11818</td><td>4.652</td><td>53.49</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>3171</td><td>0.056</td><td>2.19</td><td>0.064</td><td></td><td>1.13</td></tr><tr><td>Final</td><td>3441</td><td>0.049</td><td>0.90</td><td>0.393</td><td></td><td>1.16</td></tr><tr><td rowspan="3">Kamas<br>(0.70% out)</td><td rowspan="3">VV</td><td>Non-final</td><td>93</td><td>5.389</td><td>84.02</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>49</td><td>0.182</td><td>4.33</td><td>&lt;0.001</td><td>***</td><td>1.22</td></tr><tr><td>Final</td><td>14520</td><td>4.425</td><td>76.44</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td rowspan="3">Mojeño Trinitario<br>(1.89% out)</td><td rowspan="3">V</td><td>Non-final</td><td>1902</td><td>0.173</td><td>4.63</td><td>0.011</td><td>*</td><td></td></tr><tr><td>Penultimate</td><td>1974</td><td>0.033</td><td>0.48</td><td>0.636</td><td></td><td>1.28</td></tr><tr><td>Final</td><td>440</td><td>5.215</td><td>68.42</td><td>&lt;0.001</td><td>***</td><td>1.14</td></tr><tr><td rowspan="3">Mojeño Trinitario<br>(0.56% out)</td><td rowspan="3">VV</td><td>Non-final</td><td>90</td><td>0.097</td><td>1.40</td><td>0.228</td><td></td><td>1.14</td></tr><tr><td>Penultimate</td><td>11444</td><td>4.153</td><td>78.20</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Final</td><td>1377</td><td>0.239</td><td>14.26</td><td>&lt;0.001</td><td>***</td><td>1.34</td></tr><tr><td rowspan="3">Ruuli<br>(1.98% out)</td><td rowspan="3">V</td><td>Non-final</td><td>2215</td><td>0.278</td><td>2.27</td><td>0.028</td><td>*</td><td></td></tr><tr><td>Penultimate</td><td>2462</td><td>4.776</td><td>158.07</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Final</td><td>782</td><td>0.305</td><td>18.94</td><td>&lt;0.001</td><td>***</td><td>1.4</td></tr></tbody></table>

<figure><img src="image_11.png" /><figcaption>Fig. 6. Boxplots for duration in different syllable positions (from left to right: non-final, penultimate, final) for languages with a restricted vowel length contrast.</figcaption></figure>
<caption>Table 7</caption>

Table summarizing statistics for languages with a length contrast and without an interaction between *VowelLength* and *Position*. Columns show Language (with percentages of removed outliers in brackets), Position (Intercept is Non-final), Number of samples (N), Estimate (β), t-value, p-value, Significance level (p < 0.05 = *, p < 0.01 = **, p < 0.001 = ***)}, and Ratio (degree of lengthening between different positions) calculated as mean(Penultimate or Final)/mean(Non-final) for *Position* and mean(VV)/mean(V) for *VowelLength* (ratios are based on non-log values).

<table><thead><tr><th>Language</th><th>Length</th><th>Position</th><th>N</th><th>β</th><th>t-value</th><th>p-value</th><th>Sign.</th><th>Ratio</th></tr></thead><tbody><tr><td rowspan="4">Beja<br>(1.52% out)</td><td rowspan="4">V</td><td>Non-final</td><td>11688</td><td>4.403</td><td>66.16</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1845</td><td>0.096</td><td>5.16</td><td>&lt;0.001</td><td>***</td><td>1.13</td></tr><tr><td>Final</td><td>1654</td><td>-0.034</td><td>-0.897</td><td>0.391</td><td>***</td><td>1.16</td></tr><tr><td>LengthVV</td><td>1654</td><td>0.299</td><td>5.39</td><td>&lt;0.001</td><td>***</td><td>1.56</td></tr><tr><td rowspan="4">Beja<br>(1.10% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>9034</td><td>4.702</td><td>68.19</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1523</td><td>0.099</td><td>5.22</td><td>0.001</td><td>**</td><td>1.18</td></tr><tr><td>Final</td><td>1625</td><td>-0.0306</td><td>-0.80</td><td>0.442</td><td>**</td><td>0.96</td></tr><tr><td>LengthVV</td><td>1625</td><td>0.656</td><td>11.10</td><td>&lt;0.001</td><td>***</td><td>1.95</td></tr><tr><td rowspan="4">Bora<br>(1.67% out)</td><td rowspan="4">V</td><td>Non-final</td><td>13396</td><td>4.291</td><td>82.03</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1434</td><td>0.072</td><td>5.01</td><td>0.003</td><td>**</td><td>1.11</td></tr><tr><td>Final</td><td>2099</td><td>0.019</td><td>0.44</td><td>0.662</td><td>**</td><td>1.1</td></tr><tr><td>LengthVV</td><td>2099</td><td>0.656</td><td>11.10</td><td>&lt;0.001</td><td>***</td><td>1.95</td></tr><tr><td rowspan="4">Bora<br>(1.50% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>2768</td><td>4.941</td><td>88.32</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>474</td><td>0.074</td><td>5.25</td><td>0.002</td><td>**</td><td>1.09</td></tr><tr><td>Final</td><td>112</td><td>0.009</td><td>0.21</td><td>0.834</td><td>**</td><td>1.1</td></tr><tr><td>LengthVV</td><td>112</td><td>0.009</td><td>0.21</td><td>0.834</td><td>**</td><td>1.1</td></tr><tr><td rowspan="4">Evenki<br>(1.96% out)</td><td rowspan="4">V</td><td>Non-final</td><td>9680</td><td>4.417</td><td>70.35</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>2107</td><td>0.074</td><td>3.32</td><td>0.004</td><td>**</td><td>1.14</td></tr><tr><td>Final</td><td>2078</td><td>-0.032</td><td>-1.38</td><td>0.178</td><td>**</td><td>1.02</td></tr><tr><td>LengthVV</td><td>2078</td><td>0.328</td><td>4.44</td><td>&lt;0.001</td><td>***</td><td>1.45</td></tr><tr><td rowspan="4">Evenki<br>(1.53% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>1784</td><td>4.742</td><td>60.92</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>461</td><td>0.083</td><td>4.38</td><td>0.001</td><td>**</td><td>1.14</td></tr><tr><td>Final</td><td>710</td><td>-0.023</td><td>-1.46</td><td>0.152</td><td>**</td><td>1.05</td></tr><tr><td>LengthVV</td><td>710</td><td>-0.023</td><td>-1.46</td><td>&lt;0.001</td><td>***</td><td>1.05</td></tr><tr><td rowspan="4">Fanbyak<br>(1.90% out)</td><td rowspan="4">V</td><td>Non-final</td><td>9968</td><td>4.396</td><td>71.77</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1799</td><td>0.096</td><td>4.76</td><td>0.001</td><td>**</td><td>1.12</td></tr><tr><td>Final</td><td>1794</td><td>0.229</td><td>4.38</td><td>&lt;0.001</td><td>***</td><td>1.3</td></tr><tr><td>LengthVV</td><td>1794</td><td>0.766</td><td>10.48</td><td>&lt;0.001</td><td>***</td><td>2.07</td></tr><tr><td rowspan="4">Fanbyak<br>(1.45% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>510</td><td>5.162</td><td>72.11</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>119</td><td>0.096</td><td>4.76</td><td>0.001</td><td>**</td><td>1.02</td></tr><tr><td>Final</td><td>118</td><td>0.229</td><td>4.38</td><td>&lt;0.001</td><td>***</td><td>1.38</td></tr><tr><td>LengthVV</td><td>118</td><td>0.229</td><td>4.38</td><td>&lt;0.001</td><td>***</td><td>1.38</td></tr><tr><td rowspan="4">Resigaro<br>(1.73% out)</td><td rowspan="4">V</td><td>Non-final</td><td>9877</td><td>4.379</td><td>86.38</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>2291</td><td>0.121</td><td>3.09</td><td>0.05</td><td>*</td><td>1.18</td></tr><tr><td>Final</td><td>2625</td><td>0.019</td><td>0.28</td><td>0.794</td><td>*</td><td>1.21</td></tr><tr><td>LengthVV</td><td>2625</td><td>0.617</td><td>10.31</td><td>&lt;0.001</td><td>***</td><td>1.82</td></tr><tr><td rowspan="4">Resigaro<br>(1.47% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>2003</td><td>4.951</td><td>77.79</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>435</td><td>0.122</td><td>3.05</td><td>0.045</td><td>*</td><td>1.18</td></tr><tr><td>Final</td><td>443</td><td>0.047</td><td>0.70</td><td>0.522</td><td>*</td><td>1.16</td></tr><tr><td>LengthVV</td><td>443</td><td>0.047</td><td>0.70</td><td>0.522</td><td>*</td><td>1.16</td></tr><tr><td rowspan="4">Svan<br>(1.52% out)</td><td rowspan="4">V</td><td>Non-final</td><td>11394</td><td>4.335</td><td>51.92</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>1448</td><td>0.090</td><td>4.56</td><td>0.005</td><td>**</td><td>1.11</td></tr><tr><td>Final</td><td>1685</td><td>0.212</td><td>5.13</td><td>&lt;0.001</td><td>***</td><td>1.31</td></tr><tr><td>LengthVV</td><td>1685</td><td>0.523</td><td>6.12</td><td>&lt;0.001</td><td>***</td><td>1.78</td></tr><tr><td rowspan="4">Svan<br>(1.59% out)</td><td rowspan="4">VV</td><td>Non-final</td><td>1297</td><td>4.851</td><td>55.31</td><td>&lt;0.001</td><td>***</td><td></td></tr><tr><td>Penultimate</td><td>249</td><td>0.124</td><td>7.63</td><td>0.003</td><td>**</td><td>1.17</td></tr><tr><td>Final</td><td>127</td><td>0.278</td><td>6.98</td><td>&lt;0.001</td><td>***</td><td>1.24</td></tr></tbody></table>

<figure><img src="image_12.png" /><figcaption>Fig. 7. Boxplots for duration in different syllable positions (from left to right: non-final, penultimate, final) for languages with an unrestricted vowel length contrast.</figcaption></figure>
<figure><img src="image_13.png" /><figcaption>Fig. 8. Boxplots for duration in different syllable positions (from left to right: non-final, penultimate, final) for languages with an unrestricted vowel length contrast (continued).</figcaption></figure>

els consistently had a longer duration than short vowels.<fnref n="5" /> The phonetic correlate of phonological length was much stronger than the effect of Final Lengthening throughout the entire dataset, which means that contrasts between V and VV were maintained in all languages with phonological vowel length.

We will now discuss the four languages that showed an interaction between the two fixed effects. Araphao did not show any significant differences for *Position*, but a main effect of *VowelLength*, with VV being on average 1.75 times longer than V ($\beta = 0.58, t = 2.48, p = 0.044*$). The interaction reveals that short vowels have no significant difference between the non-final position and penultimate position ($\beta = -0.014, z = -0.461, p = 0.997$) while there is a significant effect for long vowels ($\beta = -0.136, z = -3.93, p = 0.0012*$) in penultimate position. No significant interaction was observed for final syllables. The ratios between means in *Duration* are as follows: non-final vs. penultimate V = 1.05, non-final vs. final V = 1.03, non-final vs. penultimate VV = 1.12, non-final vs. final VV = 0.97.

In Baïnounk Gubëeher, all positions showed a main effect (Penultimate: $\beta = 0.10, t = 5.29, p < 0.001$***, Final: $\beta = 0.156, t = 6.41, p < 0.001$***), i.e. all vowels in penultimate and final position were longer than in non-final position. As expected, *VowelLength* revealed a main effect with VV being on average 1.49 times longer than V ($\beta = 0.40, t = 7.25, p < 0.001$***). Additionally we found an interaction between *VowelLength* and the final position. In long vowels, the difference between non-final vs. final position was more extreme ($\beta = -0.228, t = 7.57, p < 0.001$***) than in short vowels ($\beta = -0.156, t = -6.41, p < 0.001$***) . The ratios between different positions were non-final vs. penultimate V = 1.11, non-final vs. final V = 1.26, non-final vs. penultimate VV = 1.19, non-final vs. final VV = 1.3.

Results for Dolgan were similar to Arapaho, with no effect for *Position*, but a main effect of *VowelLength* ($\beta = 0.563, t = 8.72, p < 0.001$***) . VV in Dolgan were on average 1.95 times longer than V. The interaction between *VowelLength* and *Position* was as follows. V showed no difference between the non-final and penultimate position ($\beta = -0.048, z = -1.939,$

p = 0.3781), but VV did ($\beta = -0.11, z = -3.09, p = 0.024*$), i.e. VV were lengthened in penultimate syllables. Again, no significant interaction was found for final position. The ratios were non-final vs. penultimate V = 1.08, non-final vs. final V = 1.15, non-final vs. penultimate VV = 1.18, non-final vs. final VV = 1.09.

In Movima, penultimate vowels displayed a significantly longer duration than non-final vowels ($\beta = 0.14, t = 4.9, p = 0.002$**), but there was no general significant difference between non-final and final vowels. VVs were on average 2.2 times longer than Vs ($\beta = 0.70, t = 8.83, p < 0.001$**). In addition, an interaction for *VowelLength* and final position was found. For short vowels, no significant difference between the non-final and final position was present ($\beta = -0.078, z = -1.49, p = 0.673$). However, long vowels were significantly shorter in non-final than in final position ($\beta = -0.30, z = -3.04, p = 0.029*$). The ratios between different positions were non-final vs. penultimate V = 1.12, non-final vs. final V = 1.01, non-final vs. penultimate VV = 1.07, non-final vs. final VV = 1.16.

### 3.5. Interim summary

The results presented in the previous sections can be summarized as follows. Languages without a vowel length contrast showed consistent effects of lengthening in final position, albeit with notable differences in the degree of lengthening. Lengthening of penultimate vowels was observed for some, but not all languages in this group. Languages with a restricted length contrast in which VV cannot occur word-finally varied in locus and target of lengthening, but each exhibited lengthening of at least one quantity in one position.

Languages with a vowel length contrast in all positions showed three different patterns: across-the-board lengthening of all vowels in final and penultimate syllables; lengthening in penultimate syllables only; and more complex interactions between *VowelLength* and *Position*. A pattern whereby vowels were lengthened in final but not penultimate position was not attested among our languages with a vowel length contrast.

Coming back to our initial hypotheses (see Section 1.4), we can now evaluate each of the hypotheses based on the obtained results.

<footnote n="5">⁵ We did not calculate *VowelLength* for languages with a restricted length contrast because the datasets were split into subsets containing observations for V and VV.</footnote>
(5) *Hypothesis 1*: Final Lengthening is attested in natural speech from a world-wide sample of 25 languages.

The first hypothesis was confirmed. We observed a signifi-
cant increase in vowel duration of non-long vowels in final syl-
lables, and in some cases also in penultimate syllables, in our
world-wide sample of 25 languages.

(6) *Hypothesis 2*: Phonological vowel length interacts with Final Lengthening.

This hypothesis was also confirmed. We found an interac-
tion between *VowelLength* and *Position*. The observed interac-
tion exhibits progressive lengthening of short vowels in
penultimate and final position, while long vowels were length-
ened only in penultimate position. No interaction was found
between penultimate and final position.

Further evidence was provided by means of inspecting indi-
vidual languages. We found crucial differences between lan-
guages with a length contrast and those without a length
contrast. The most striking difference is that all languages with-
out phonological vowel length in our sample attested FL in final
position, while in languages with a vowel length contrast, we
sometimes find evidence for FL on the penultimate syllable
only, or an interaction between *VowelLength* and *Position*.

Another result was that vowel length contrasts are main-
tained under Final Lengthening. The effect of phonological
length on vowel duration was substantially stronger than any
positional effects. This means that we could not find any evi-
dence of contrast neutralization induced by Final Lengthening.

The evidence as to whether the presence of phonological
length may inhibit Final Lengthening remains inconclusive.
We found limited effects of FL in two languages from the group
of languages with a V/VV contrast (Arapaho, Dolgan), with a
significant effect only in one position for one length type. How-
ever, there are several languages in the same group that show
strong across-the-board effects of Final Lengthening (Baï-
nounk Gubëeher, Fanbyak, Svan). This suggests that the pres-
ence of a V/VV contrast does not necessarily have an
inhibitory effect on FL.

4. Discussion

4.1. General observations

The results presented in the previous section offer new
insights into the nature of Final Lengthening in the world's lan-
guages based on a broad cross-linguistic sample. Our study
revealed that short vowels are progressively lengthened from
non-final to penultimate to final position across languages. It
also provides a comprehensive demonstration of the interac-
tion between *VowelLength* and *Position* for languages with a
phonological vowel length contrast.

As opposed to many previous studies, our study is based
on natural speech from language documentation corpora
which were obviously not created for the purpose of this study,
and therefore contain considerable “noise”, reflected by, e.g.,
heterogeneity in terms of number of speakers per corpus.
We believe that this variation is not a disadvantage but instead
comes with notable benefits, particularly because it allows for
“more ecologically valid and wide-reaching generalizations”

(Winter & Grice, 2021, p. 1269) compared to data obtained
in well-controlled laboratory settings. Ideally, both experimen-
tal and corpus-based evidence should be used to inform
linguistic inquiry, as both types of evidence complement each
other.

Below we formulate four general cross-linguistic observa-
tions about Final Lengthening and its interaction with vowel
length, based on the results discussed in Section 3.

(7) *Observation 1*: Final Lengthening is a common process across languages from different families and macro-areas.

(8) Observation 2: Final Lengthening shows considerable cross-
linguistic variation with respect to its scope and degree.

(9) Observation 3: Languages with a phonological length contrast show a particular high degree of variation. Some may show an interaction between length and position, while others may not. There is a tendency for lengthening to affect VV stronger than V in languages with a length contrast. FL may also be limited in scope to the penultimate syllable.

(10) *Observation 4:* The degree of lengthening by position is con-
sistently smaller than the difference between members of a pair
of phonological short and long vowels. The quantity contrast
remains stable across positions, as short vowels under the influ-
ence of Final Lengthening still have a shorter average duration than
(non-lengthened) long vowels.

4.2. The phonological nature of Final Lengthening

The present study has revealed that Final Lengthening
operates in a highly language-specific way. While we cannot
rule out a certain effect of general motor constraints as dis-
cussed by Berkovits (1994) and Cho (2016), FL must be de-
ply entrenched in the phonology of individual languages and
naturally interacts with other aspects of phonology such as
phonological length. It thus makes sense to ask how exactly
FL interacts with other segmental and suprasegmental fea-
tures that are also part of a language's grammar.

A factor that is likely to interact with Final Lengthening is the
sound inventory of a language. Most languages in our sample
had fully symmetrical vowel systems, but three had at least
one unpaired vowel: Kamas, Evenki, and Svan. One could
expect them to form a middle ground between fully symmetri-
cal languages and languages without vowel length, and one
could further expect a preference for lengthening short vowels
because there is a lower risk of confusing unpaired vowels that
receive an extra duration boost. However, our data do not offer
evidence to corroborate such a conjecture.

Another potentially relevant aspect of sound inventory are
other sound classes where length can be contrastive, in partic-
ular geminates and diphthongs. If a language uses length con-
trastively not only for vowels but also for other segment types,
length will have a higher functional load in that language, and
durational cues could potentially be more robust against proso-
dic modulation. And indeed, this may be one of the reasons for
the limited evidence of FL in Arapaho and Dolgan, where no
lengthening was observed except for VV in penultimate sylla-
bles. Dolgan is a language with a fair number of geminate
stops, affricates and sonorants. The following geminates are
attested in the Dolgan DoReCo dataset: /p/, t, k,, m, n,
ŋ, I, /a/. Arapaho has no geminates, but instead distinguishes
long and short diphthongs: /ei, ei, ow, ow, ai, ai/. If length
is used contrastively not only in vowel monophthongs but also
elsewhere, this may help explain the inhibition of additional
length manipulation at phrase boundaries. Moreover, Arapaho
is a tone language, and tone languages are notorious for com-
plex length-tone interactions at the word and the phrase level
(Yip, 2007). Further research will have to look more closely into
how this affects Final Lengthening. While functional load may
be insightful when considering individual languages, it was
not an overall good predictor for Final Lengthening, as most
languages that use vowel length contrastively still showed an
effect of Final Lengthening. This finding is in line with what
Lunden et al. (2017) observed for the relation between duration
and stress.

The final position of a prosodic domain has a special status
that is usually associated with neutralization and loss of con-
trast. Hyman (2009) argues that the final position is not an
ideal place for tonal, segmental or quantity contrasts, and cites
numerous examples of final vowel shortening (FVS) from var-
ious Bantu languages. Ruuli, a Bantu language included in our
sample, also exhibits a phonological process of FVS: long
vowels are disallowed in word-final position, and vowels that
would surface as long elsewhere are short when they appear
word-finally. The overall preference for contrasts to be realized
in non-final position would offer a natural explanation for the
existence of the restricted length contrast type, and may addi-
tionally offer an explanation for the shift of lengthening to the
penultimate position in languages with an unrestricted length
contrast. It should be kept in mind though that maintaining
quantity contrasts in all positions is a much more common pat-
tern cross-linguistically, and our acoustic measurements do not
lend support for Final Lengthening being a trigger of contrast
neutralization.

Another phonological process that is likely to interact with
vowel length is final vowel devoicing, which is particularly wide-
spread in South American languages and is often accompa-
nied by shortening. In our sample, final vowel devoicing is
attested in Bora and Resígaro. Due to devoicing, some vowels
were reduced to an extent that they could not be detected in
the acoustic signal anymore, in which cases they were
removed from the transcription during data pre-processing in
DoReCo. As a result, a final vowel in the closed syllable on
the surface sometimes corresponds to an underlying penulti-
mate vowel. This discrepancy may then mask the site of Final
Lengthening in these languages.

Another potential test case for the interaction of FL with
phonological features is the behavior of long vowels, which
under Final Lengthening can become (phonetically) overlong.
On the phonemic level, overlong vowels are extremely rare
cross-linguistically. According to Moran and McCloy (2019),
less than 1% of the world's languages have a ternary quantity
system with overlong segments, and it seems reasonable to
assume that overlong segments are highly marked structures.<fnref n="6" />
Whether or not this may contribute to reducing of FL in some V/
VV languages remains an open question for now, because we
did not find a general trend against FL on VV vowels. On the

contrary, our results largely corroborate previous observations
on Uralic languages (Krull, 1997; White & Mády, 2008; Nakai
et al., 2012) that VV are *preferred* targets for Final Lengthening.

A final point for consideration is syllable structure. Vowels in
closed syllables are usually shorter than in open syllables
(Gordon, 2006). If a language tends to have more closed syl-
lables word-finally than word-medially, or vice versa, then this
will skew the durational measures for these positions. While
it is beyond the scope of this paper to analyze syllable struc-
ture in more detail, one language where it may be relevant is
Beja. According to the results in Table 7, Beja VV show signif-
icant lengthening in the penultimate syllable but a slight (non-
significant) shortening in the final syllable. Beja is a synthetic
languages in which some of the grammatical markers that
often occur phrase-finally have the shape -(C) V:C. Examples
include -i:n ‘AOR.3PL’, =ho.b ‘when’, =e:k ‘if’, but also a number of
frequent lexical items such as the pronoun ane:b ‘1SG.ACC’, the
postposition dha:j ‘DIR’, and the verb e:n ‘they said’. The shorter
duration of long vowels in final syllables in Beja may thus be
contingent on the frequency of closed heavy syllables appear-
ing in phrase-final position.

4.3. *Theoretical implications*

A prominent theory of Final Lengthening is the π-gesture
theory (Byrd & Saltzman, 2003), which assumes a prosodic
gesture called π-gesture at phrase boundaries. This π-
gesture controls articulatory timing in the vicinity of a prosodic
juncture, and when it overlaps with segmental articulatory ges-
tures, the result is a slowing of gestural activation and, in con-
sequence, longer segment durations. The π-gesture model
explains lengthening of pre-boundary segments, and can
explain our results for non-long vowels (see Section 3.1). How-
ever, the interaction between position and vowel length intro-
duces some complications. Here, the π-gesture model has to
allow for flexible association of π with designated prosodic
positions or apply different rules for long vowels. As Turk and
Shattuck-Hufnagel (2007) and Katsika (2016) have shown,
the presence of local prominence such as stressed syllables
may alter the scope of lengthening and further constrain its
effect (see also Krivokapić, 2014). If long vowels constitute
equally prominent positions, or phonological length is corre-
lated with prosodic prominence in a language, one would
expect long vowels to attract π. This could then explain some
of observed variation in languages with a V/VV contrast. How-
ever, since word-level prominence is still not well understood
for several of the languages included in our study, we can only
speculate on this potential interaction at this point.

4.4. Outlook

As more data from hitherto understudied languages
become available for cross-linguistic research due to endeav-
ors such as DoReCo, it becomes more and more feasible to
tackle questions of what aspects of prosody are truly common
cross-linguistically (and potentially universal), and how pro-
pody interacts with language-specific properties.

We would encourage future studies on Final Lengthening
and other durational aspects of speech in general to take into
account additional factors which we were not able to control for

<footnote n="6">⁶ Even within languages that allow phonologically overlong vowels, these vowels are often subject to further restrictions. For example, in Shilluk, a West Nilotic language, overlong VVV only occur in nominal and verbal bases but not in affixes (Remijsen et al., 2019; Remijsen & Ayoker, 2020).</footnote>
in the present study. Some languages have word-level stress, others have pitch accent, and yet others have complex tone systems. Tone is known to interact with position and vowel length in intricateways. And while stress is known to have a weaker durational effect than Final Lengthening, it may still interact with Final Lengthening, e.g. by shifting the locus of lengthening to the stressed syllable. The study is based on language documentation data, but ideally one would check the results with controlled experiments with native speakers in cases where this is possible (Kamas, for example, is extinct, and the dataset analyzed contains recordings of the last native speaker from the 1960s). As far as the sample is concerned, including one or two languages with a ternary quantity system would also be desirable, as so far empirical coverage of Final Lengthening in such languages (e.g. Plüschke & Harrington, 2013 for Estonian) is very limited.

A potential limitation is that the present study looked at seg-
mental durations before silent pauses, which do not necessar-
ily have to conicide with prosodic boundaries. While silent
pauses were identified using criteria such as rhythmic integra-
tion during data processing in DoReCo, there will be cases in
which a vowel before a silent pause is counted as *final* even
though it is not adjacent to a prosodic boundary, as well as
cases where a vowel is counted as *non-final* when it precedes
a prosodic boundary that is not accompanied by a pause. Ide-
ally, one would enrich the existing data from DoReCo with
annotations of prosodic boundaries to further illuminate the
relation between prosodic structure, pauses, and lengthening.

5. Conclusion

In this paper, we investigated the duration of vowels in final, penultimate and non-final syllables across a diverse sample of 25 languages. We found a strong tendency for languages to lengthen vowels in at least one of the two syllables before a pause. Languages differed dramatically with respect to the scope and degree of Final Lengthening. Phonological length contrasts remained stable and were not neutralized by Final Lengthening. These results suggest that Final Lengthening is a prosodic phenomenon rooted in the phonology of a given language, and its manifestation shaped by a mandate for contrast preservation. Our data provide the strongest demonstration to date that Final Lengthening is attested across a large set of languages from six macro-areas and various language families around the globe.

This paper has also demonstrated the feasibility of conduct-
ing phonetic studies on language documentation data. Despite
the obvious limitations in terms of factors that cannot be easily
controlled for when working with fieldwork data, we hope to
have shown the value of mobilizing fieldwork data for linguistic
research as one measure to address the still persistent
"WEIRDness" (Henrich, Heine, & Norenzayan, 2010) in the
cognitive sciences.

Acknowledgements

This work was supported by an ANR-DFG grant (ANR-18FRAL-
0010-01, DFG-KR951/17-1) to Frank Seifart and François Pellegrino.
We would like to thank Bodo Winter for statistical advice and Jelena
Krivokapić, Marija Tabain and one anonymous reviewer for construc-
tive comments and feedback.

**Appendix A. Phonological profiles**

In this appendix, we present relevant phonological back-
ground for the 25 languages analyzed in our study, in particular
with respect to vowel inventories, and motivate our decisions
for excluding certain segments from our study. Note that we
reproduce the phonetic symbols found in the respective
sources and do not attempt to provide our own reanalyses.<fnref n="7" />
Commentary about word prosody is provided for those lan-
guages for which prosody is sufficiently described.

Arapaho Arapaho (arap1274, Algic) has four short and four long vowels (11). The quantitative difference is accompanied by a qualitative difference in that especially the long high vowels are slightly more raised. In addition, Arapaho has three diphthongs, all of which can be long or short: /ei/, /ei/, /ow/, /ow/, /ai/, /ai/. Cowell & Moss (2008), p.15 mention /ie/ as a fourth marginal diphthong, but this sound is not attested in our sample.

<figure><img src="image_14.png" /></figure>

Syllable structure in Arapaho is CV(C)(C). An epenthetic [h] is added at the beginning of words that start with an underly- ingly V-initial root or prefix. Arapaho has a tone or “pitch accent” system that contrasts H and Ø (absence of tone). Tone has both lexical and grammatical functions and interacts with various other phonological processes; for more details, see Cowell and Moss (2008).

Baïnounk Gubëeher Baïnounk Gubëeher (gube1234, Atlan-
tic–Congo) is a non-Bantu minority language of Senegal. It has
ten vowel qualities, and all vowels can be long or short, making
for a total of twenty vowel phonemes (12). The lax vowels /ɪ/, /ɪ/
and /ʊ/, /ʊ/ are marginal, as they are acoustically hard to distin-
guish from /i/, /i/ and /u/, /u/., and minimal pairs are rare
(Cobbinah, 2013, p. 166–168). Out of a total of 27,172 vowel
tokens in the Baïnounk Gubëeher (raw) dataset, there were
73 /ʊ/, 46 /ʊ/, one /ɪ/ and four /ɪ/. For that reason, /ɪ/ and /ɪ/
were excluded from our analysis.

<figure><img src="image_15.png" /></figure>

Baïnounk Gubëeher has word-level stress with pitch as the main acoustic correlate of accent (Alexander Yao Cobbinah, p. c.). The details of word- and phrase-level prosody in Baïnounk Gubëeher still await further scrutinization.

<footnote n="7">⁷ The vowel charts were created using the *vowel* package in LATEX, which is responsible for the somewhat idealized positioning of some symbols, especially low front /a/.</footnote>
**Beja** The Sinkat variety of Beja (beja1238, Afro-Asiatic) represented in our sample has five long and three short vowels (13). The short vowels are /i/, /e/, and /a/, though /e/ is marginal and never contrasts with /e:/ or /i/. Due to various phonological processes such as coloring and deaccentuation, short [o] and [u] can occur in surface forms and are represented as such in our transcriptions (Vanhove, 2017, p. 17).

<figure><img src="image_16.png" /></figure>

Beja has contrastive stress that falls on one of the final three syllables in a word. Roots, inflectional affixes and clitics may all bear stress, and its placement is determined by a complex interplay of lexical specification and morphological rules.

**Bora** Bora (bora1263, Boran) has a cross-linguistically rather unusual vowel space with three high unrounded vowels (Parker, 2001) (14). All seven vowels can be long or short (Thiesen & Weber, 2012).

<figure><img src="image_17.png" /></figure>

Bora has two phonological tones which sometimes interact with vowel length, especially in phrase-final position (see Thiesen & Weber, 2012, p. 70–75). Syllable structure in Bora is (C)V(V)(C), with the following additional restrictions: (i) long vowels only occur in open syllables, (ii) coda Cs can only be /h/ and /?/, (iii) closed syllables are not allowed word-finally. As word-final vowels are sometimes deleted, surface forms may contain a final closed syllable.

**Dalabon** The vowel chart of Dalabon (ngal1292, Guninyguan) is shown in (15). Ponsonnet (2014) states that the high central vowel /u/ is marginal, and that most speakers pronounce /u/ instead.<fnref n="8" /> Ponsonnet (2014) also states that Dalabon has nine diphthongs; these were treated as vowel-glide sequences in the DoReCo dataset, however, and their phonological status needs to be further explored.

<figure><img src="image_18.png" /></figure>

Dalabon has non-contrastive word-initial stress; the exact acoustic correlates of stress in Dalabon demand more careful scrutiny, however.

**Dolgan** The vowel inventory of Dolgan (dolg1241, Turkic) is given in (16). In addition, Dolgan has the diphthongs /ie/, /uo/, /yø/, /ia/ (Artem'yev & Petrov, 2003).

<figure><img src="image_19.png" /></figure>

**English (Southern England)** This variety of English (sout3282, Indo-European) is a group of dialects spoken in the south of England. The recordings analyzed in this study were made with speakers from Kent and thus represent a variety of Southeastern English (sout3285). Notable features of this dialect include rhotacism and optional final stop deletion. As a best approximation, we used the pre-trained British English language model of WebMAUS and manually adapted the resulting phone alignments to account for the most striking differences in pronunciation. The pre-defined WebMAUS model for British English contains the monophthongs in (17) and the diphthongs /eə/, /iə/, /aʊ/, /əʊ/, /eɪ/, /əɪ/, /ɔɪ/, /ɔʊ/, /aɪ/.

<figure><img src="image_20.png" /></figure>

We excluded the vowels /ɪ/ and /ɪ:/ from our sample as they had only a handful of occurrences in final position. /ɪ:/ in particular regularly caused trouble for the forced aligner because that vowel is rhotacized in Southern English from Kent.

**Evenki** Evenki (even1259, Tungusic) has five short and six long vowel phonemes, /e:/ being the only unpaired vowel (short [e] occurs in loan words). The vowel chart is given in (18).

<figure><img src="image_21.png" /></figure>

Syllable structure in Evenki is (C)V(V)(C), and loan words strictly conform to this pattern. Word stress is free, and any syllable can bear stress, though Bulatova and Grenoble (1999) note there is a certain tendency for open final syllables to attract stress.

<footnote n="8">⁸ There was a total of 60 occurrences of this vowel in our dataset, which was mapped to /i/ rather than /u/ since its was realized as an unrounded vowel in most cases.</footnote>
Fanbyak Fanbyak (orko1234, Austronesian), also known as Orkon, is spoken by ca. 130 speakers on the island of Ambrym, Vanuatu (Franjieh, 2019). Fanbyak has a symmetrical seven-vowel inventory with long and short vowels (19). The vowel /o/ is quite rare and occurs only in a handful of lexical items; the same is true for its long counterpart /o/, which can also be derived by morphophonemics, however.

<figure><img src="image_22.png" /></figure>

Syllable structure is (C)V(C), where palatalized and labialized consonants count as single Cs. Fanbyak is still a largely underdescribed language, especially with regards to its prosody, so little can be said about tone, stress, or accent.

Gurindji Gurindji (guri1247, Pama-Nyungan) has a three-vowel system typical of most Australian languages (20). There is a fair amount of allophony for all vowels depending on the consonantal context (Felicity Meakins, p.c.). Gurindji also has three diphthongs /ei, əi, oi/. Gurindji has been reported to have a vowel length contrast for all three monophthongs. However, the long vowel phonemes in Gurindji are marginal and occur in only a handful of lexical items (Jones, Meakins, & Buchan, 2011, p. 309). This is also reflected in the DoReCo Gurindji dataset, where less than 0.5% (60/13869) of all monophthongs are long. On these grounds, we excluded long vowels from our analysis and treat Gurindji as a language with no length contrast.

<figure><img src="image_23.png" /></figure>

Since Gurindji is relatively underdescribed and exposed to considerable influence from both English and Gurindji Kriol, regretfully little can be said about its word- and phrase-level prosody. A plausible assumption would be that Gurindji has fixed word-initial stress, as most Australian languages do (Dixon, 2002).

Jejuan The vowel system of Jejuan (jeju1234, Koreanic) comprises nine monophthongs with no length contrast (21). The pronunciation of /e/ and /a/ appears to be quite flexible, and one can find various transcription variants in the literature. Cho, Jun, Jung, and Ladefoged (2000) transcribe them as <æ> and <ʌ> and report a merger with /e/ and /o/ for younger speakers. There is some debate in the literature about the status of certain stop-glide sequences, which Kim (2018), but not Jung (2013) and Yang, Yang, and O'Grady (2019), analyze as single labialized phonemes. In the Jejuan DoReCo dataset, glides are always treated as separate segments.

<figure><img src="image_24.png" /></figure>

Syllable structure in Jejuan is (C)(G)V(C) with a clear tendency for filled onsets. Jejuan is non-tonal, but the status of stress is still unresolved, as it is sometimes described as word-initial (Kim, 2018) and sometimes as entirely absent from the prosody of the language (Jung, 2013; Yang et al., 2019).

Kamas Kamas (kama1378, Uralic; also known as Kamasian) is an extinct Samoyedic language and one of the most underdescribed languages in our sample. The vowel inventory of the speaker included in the DoReCo dataset, who was the last native speaker at the time of recording and passed away in 1989, is given in (22). Note that this speaker lacks the vowels /y/ and /ø/, which have been described for other speakers of Kamas.

<figure><img src="image_25.png" /></figure>

The data used for the present study come from the INEL Kamas corpus (Klooster, Tiina, Wagner-Nagy, & Arkhipov, 2021), in which vowel length is marked according to the following principles: “the only words where the long vowels are marked are words where long vowels have emerged as a result of contraction inside the stem” (Arkhipov, Däbritz, & Gusev, 2018, p. 5).

Lower Sorbian The basic vowel inventory of Lower Sorbian (lowe1385, Indo-European) is shown in (23), based on Schaarschmidt (1997). The Lower Sorbian orthography distinguishes several allophonic variants that are faithfully represented in our mapping table, which is why /e/, /i/, /o/, and /i/ (but not [e]) also appear as distinct segments in the dataset. Words of German or Polish origin were systematically labeled as non-native and excluded from the analysis, so phones such as [y] are not present in our sample.

<figure><img src="image_26.png" /></figure>

Movima Movima (movi1243, isolate) is spoken in northern Bolivia and has five long and five short vowels (24). Apart from inherent length, Movima also has a process of penultimate
lengthening that lengthens a penultimate open syllable in a word. This process is blurred by a number of lexical exceptions and by cliticization, resulting in a largely unpredictable distribution of length in surface forms. Stress in Movima too normally falls on the penultimate, but as stress and length are independent properties governed by different principles, their loci do not always coincide (Haude, 2006, p. 47ff).

<figure><img src="image_27.png" /></figure>

Mojeño Trinitario Mojeño Trinitario (trin1278, Arawakan) has a five-vowel system and a quantity opposition for all five vowels (25). There is also one diphthong /æə/ with its long counterpart /æə:/ that may variably be pronounced as [i] or [ɛ] and [i:] or [ɛ:] respectively (Rose, 2014a). Since the majority of occurrences of this sound in our data were phonetic diphthongs, we did not include them in our sample.

<figure><img src="image_28.png" /></figure>

Stress normally falls on the penultimate syllable of the word, though there are some lexical exceptions, as well as several extrametrical suffixes. There is a complex set of rules governing rhythmic vowel deletion and compensatory lengthening (see Rose, 2014b), but the transcription follows the surface forms. Like Kamas and Ruuli, Mojeño Trinitario does not allow long vowels word-finally.

N||ng N||ng (Tuu, nngg1234) is a nearly extinct and underdescribed language of South Africa. N||ng has a remarkably complex sound inventory with approximately 70 consonants, including clicks contrasting five places of articulation (/ɔ/, /|/, /!/ , /||/, /h/). The basic vowel inventory of N||ng comprises the five cardinal vowels /a/, /e/, /i/, /o/, /u/, as well as several nasalized, epiglottalized, and nasalized-epiglottalized variants. Due to the scarcity of descriptive materials and the uncertainties regarding the exact composition of the N||ng sound inventory, we have opted for a practical solution and took the transcriptions in our dataset at face value. The vowels attested in our sample are shown in (26). This inventory is almost identical to the one described in Exter (2008), the only exception being /ũ³/, which is not attested in our data (and is considered marginal in Miller et al., 2007).

N||ng attests a number of surface diphthongs whose phonological status is not entirely clear. Miller et al. (2007) list 20 diphthongs without specifying which of them (if any) are to be considered underlying. Exter (2008) generally treats phonetic diphthongs as sequences of underlying monophthongs

but argues that some of these sequences may in fact have been rephonologized as diphthongs. Due to the uncertain status of diphthongs, we have opted for a 1:1 mapping of all vowel symbols to monophthongs. For example, the word ||'æ' 'go' is mapped to /||', /a/, and /e/.

<figure><img src="image_29.png" /></figure>

Syllable structure in N||ng is CV(V)(C) or (C)V(C), depending on the analysis of diphthongs. N||ng is a tone language with two lexical tones (L, H) and the mora as the TBU (55 Exter, 2008). The exact mechanics of tone in N||ng are not fully understood, and Miller et al. (2009) note that “the situation is complicated by the influence of Afrikaans prosody” (ibid, 131).

Resígaro Resígaro (resi1247, Arawakan) is a moribund language once spoken in Southern Colombia, in close contact with Bora. Following Allin (1976), Resígaro has five vowels, each of which can be long or short (27). The syllable structure of Resígaro is (C)V(C), where V can be either long or short and only glottal stops may appear in the coda. Resígaro has two tones, high and low.

<figure><img src="image_30.png" /></figure>

Ruuli Ruruuli-Lunyala (ruul1235, Atlantic–Congo, referred to here by its spelling variant Ruuli) is a Bantu language with five short and five long vowels and three diphthongs /aɪ/, /eɪ/ and /oɪ/ (28). Vowel length is distinctive. According to Namyalo et al. (2020), there are a number of phonological processes that lengthen short vowels in certain segmental environments, e.g. before NC sequences and after CG sequences. The transcriptions used in this study reflect the result of these processes rather than underlying vowel length. Long vowels are categorically excluded from word-final position, and this constraint outranks all other processes that would normally yield long vowels.<fnref n="9" />

<figure><img src="image_31.png" /></figure>

<footnote n="9">⁹ Loan words may end in a final long vowel; these words were labeled as foreign material in DoReCo and are therefore not included in our study.</footnote>
Ruuli is a tonal language with H, L and Ø tones. Syllable structure can be described by the templates (C)V(V), N, CGV, NCV(V), (N)(C)GV, and CCV(V). Closed syllables are thus not found in underlying forms, and are extremely rare in surface forms.

Sadu The vowel system of the variety of Sadu (sadu1234; Sino-Tibetan) represented in DoReCo is shown in (29). In addition, Sadu also has a syllabic fricative /z/, as well as five diphthongs /ua/, /aɪ/, /aɪ/, /oɪ/, and /ui/. The syllabic fricative /z/ was included in our study, just as the syllabic Cs in the related language Yongning Na. /z/ behaves like a vowel phonologically and its frequency of occurrence is comparable to that of other vowels: there were 334 tokens of /z/ in our sample, while there were 143 tokens of /ɔ/ (the least frequent vowel) and 2992 tokens of /a/ (the most frequent vowel).

<figure><img src="image_32.png" /></figure>

Sanzhi Dargwa Sanzhi Dargwa (sanz1248, Nakh-Dagestanian) has four plain and three pharyngealized vowels (30). Following Forker (2020), we treat sequences of two identical vowels as two separate short vowels.

<figure><img src="image_33.png" /></figure>

Syllable structure in Sanzhi Dargwa can be described by the template (C)V(C)(C). Sanzhi Dargwa is a non-tonal language, but stress is lexically contrastive, and certain affixes such as plural suffixes of nouns attract stress (Forker, 2020, p. 30).

Svan The DoReCo dataset of Svan (svan1243, Kartvelian) contains recordings of speakers from two dialects (Lashkuri and Choluruli) with largely overlapping vowel inventories (31). The phonologically divergent Upper Bal variety of Svan, which attests several additional sounds such as /æ:/, /ø/, /ø:/, /y/, and /y:/ (Tuite, 1998), is not part of our sample.

<figure><img src="image_34.png" /></figure>

Urum Urum (urum1249, Turkic) has a nine-vowel system shown in (32). The transcriptions in the corpus, which were created by a native speaker of the language, contain several instances of letter repetitions: <ii>, <ää>, and <aa>. Impressionistically, the corresponding sounds do resemble long vowels. It is not clear what is responsible for their increased duration, but likely candidates are stress, syllable structure and word minimality constraints. Since there are no minimal pairs distinguished by vowel length, and vowel length is not known to have any phonological relevance elsewhere in Urum, we adopt a conservative stance and follow Skopeteas (2016) in not considering vowel length a phonological feature in Urum.

<figure><img src="image_35.png" /></figure>

Vera'a Vera'a (vera1241, Austronesian) has seven vowel phonemes, as shown in (33). The mid-high vowels are slightly more raised than cardinal /e/ and /o/. The basic syllable structure is (C)V(C), but clusters do occur in certain conditions; see Schnell (2011) for further discussion.

<figure><img src="image_36.png" /></figure>

Yali Yali data in DoReCo represent the Apahapsili variety (apah1238, Nuclear Trans-New Guinea), which has a simple five-vowel inventory (34). The Angguruk dialect has two additional phonemes, /i/ and /u/, which have merged with /i/ and /u/ in Apahapsili (Riesberg, Zöllner, & Ilse, 2017, p. 10). Note that loans from Papuan Malay were not part of the analyzed dataset, and vowels from that lexical stratum do therefore not occur in the current study.

<figure><img src="image_37.png" /></figure>

Yongning Na Yongning Na (yong1288, Sino-Tibetan) has nine base vowels and no phonological quantity opposition (35). Some of these vowels have a nasalized counterpart (/ɪ/, /æ/, /ɑ/, /ɔ/) whose distribution is mostly restricted to syllables with /h/ as an onset. In addition, Yongning Na has two syllabic consonants /v/ and /ɪ/ that can form valid syllable
rhymes, bear tones, and the former may also be nasalized. Syllability was systematically marked in the original transcriptions, which made it possible to unambiguously distinguish syllabic from non-syllabic consonants. /v/ is a highly frequent sound, well within the range of other vocoids, with 1722 occurrences in our sample compared to 459 tokens of /ɑ/ and 3676 tokens of /ɪl/. For more information on Yongning Na phonology, see Michaud (2017).

<figure><img src="image_38.png" /></figure>

For the purpose of this study, we included all plain and nasalized vowels as well as syllabic consonants with the exception of /ɑ/ and /y/, which had to be discarded due to their infrequency in final syllables (penultimate: 1 occurrence each, ultimate: 1 occurrence of /y/ and 3 occurrences of /ɑ/).

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