V e L e P a: a Verbal Lexicon of P ame (2024)

Abstract: This paper presents VeLePa, an inflected verbal lexicon of Central Pame (pbs, cent2154), an Otomanguean language from Mexico. This resource contains 12528 words in phonological form representing the complete inflectional paradigms of 216 verbs, supplemented with use frequencies. Computer-operable (CLDF) inflected lexicons of non-WEIRD underresourced languages are urgently needed to expand digital capacities in this languages (e.g. in NLP). VeLePa contributes to this, and does so with data from a language which is morphologically extraordinary, with unusually high levels of irregularity and multiple conjugations at various loci within the word: prefixes, stems, tone, and suffixes constitute different albeit interrelated subsystems of inflection.

## introduction central pame is an indigenous mesoamerican language spoken by around 5000 people in and around santa maría acapulco @xcite . the language is still acquired as a first language by children in various communities, but is endangered by the expansion of spanish. the language lacks a standard written form, and extant documentation (e.g. @xcite @xcite is insufficient, undigitized, and computationally largely unusable. the language, however, like others in its family (e.g. chichimec, see @xcite is a treasure trove of morphological complexity, due to the combination of the following two traits: ## building velepa to build an inflected lexicon of central pame verbs the first thing we need is language documentation. although some inflectional paradigms were collected by sil missionaries around 70 years ago @xcite , these are insufficient in number and are hardly usable computationally due to inconsistencies. over the last four years, i have been documenting the language together with native speakers, mostly through the elicitation of inflected forms. for their orthographic transcription i adopt a phonemic approach, whereby only contrastive sounds are represented with different characters. international phonetic alphabet conventions are followed, as in the aforementioned previous work on the language. i thus avoid the problems of a spanish-based orthography that is occasionally used to write the language locally and which does not represent features like vowel nasality, tone, consonant length, and the contrast between an mid-open and mid-closed front vowels. the database (velepa) that is presented in this paper contains therefore the complete paradigms of a large number of verbs in phonological form. every single one of the 12528 inflected forms that velepa contains (all 58 forms from 216 verbs) has been independently elicited (i.e. never extrapolated from other forms, as is often the case of these recources) and checked multiple times to avoid mistakes and inconsistencies (e.g. in the treatment of synonymous inflected forms like dived-dove). this is needed, first, because the language demands it. most of the words in velepa (74%) have different forms, and syncretism (i.e. morphological whole-word identity) is never the result of different values being systematically the same across all lemmas as in other languages (e.g. english do inf, do 1sg.prs, do 2sg.prs, do 1pl.prs, do 2pl.prs, do 3pl.prs). ## analysis of system complexity on the basis of velepa, freely available online at https://osf.io/xhyzm/?@xmath0, i analyze the morphological complexity and the predictability of the inflectional system as per the paradigm cell filling problem (see @xcite . as mentioned in the introduction, one of the key idiosyncratic features of the language is the relative independence of prefixal, suffixal, tonal, and stem morphology. these four layers are analyzed separately below, through the following software: ## discussion an inflectional system with the complexity of any of these layers would be considered quite complex. the (in)famous latin verbs, for example, have 4 principal parts, 0.28 bits of average conditional entropies, and 15 zones of interpredictability (see @xcite ), yet this is almost consistently simpler than any of the inflectional subsystems that coexist within pame verbs. the overall system, hence, would appear to test the very limits of human linguistic cognition. how do speakers manage to successfully learn and use a system like this? the answer might lie in predictability between inflectional layers. while that between cells is explored more often, as i have done in the previous section 3, this does not mean that predictability between different slots or properties of a single word plays no role. preliminary assessment of how much information one layer provides about another in pame can be obtained from normalized mutual information (nmu), calculated through the r package aricode @xcite . results in a final challenge that pame verbs present is what erdmann et al. (2020) have called the paradigm identification problem. given the amount of suppletion, stem alternation and allomorphy in the system, predicting the lemma and morphosyntactic value of a form from its morphology must also be complicated. the same markers are reused with different functions in different verbs classes (as show in ## conclusion this paper has reported on the compilation of a verbal lexicon of pame (velepa), specifically with computational applications in mind. it has also presented some preliminary quantitative analyses of this inflectional system around the topics of the paradigm cell filling problem, and related challenges that speakers and learners of a language face when using and/or acquiring inflectional morphological patterns. this system, like other otomanguean ones (see e.g. @xcite ) is remarkable because its morphology deviates very significantly and in several dimensions from the canonical @xcite ) most straightforward one. it is structured into several morphological slots which work together (see the phenomena of multiple, distributed or extended exponence, harris 2017) into expressing tenseaspect-mood and subject person-number values. each slot is, furthermore, organized into a large number of inflection classes and contains multiple isolated irregularities. velepa is expected to contribute to both theoretical linguistic analysis and to nlp, allowing the inclusion (e.g. into reinflection tasks) of a language that is both highly complex and typologically very different from the better documented (indo-)european ones.