Schwa-deletion in G erman noun-noun compounds (2020)

Abstract: We report ongoing research on linking elements in German compounds, with a focus on noun-noun compounds in which the first constituent is ending in schwa. We present a corpus of about 3000 nouns ending in schwa, annotated for various phonological and morpho-syntactic features, and critically, the dominant linking strategy. The corpus analysis is complemented by an unsuccessful attempt to train neural networks and by a pilot experiment asking native speakers to indicate their preferred linking strategy. In addition to existing nouns, the experimental stimuli included nonce words, also ending in schwa. While neither the corpus study nor the experiment offer a clear picture, the results nevertheless provide interesting insights into the intricacies of German compounding. Overall, we find a predominance of the paradigmatic linking element -n for feminine and masculine nouns. At the same time, the results for nonce words show that -n is not a default strategy.

## introduction german compounds and especially noun-noun compounds often include a linking element (le), i.e. segmental material between the two constituents of a compound, such as -s in liebesbrief 'love letter' (liebe-s-brief [love-le-letter]) or -er in kindergarten 'nursery @xcite ). though linking elements are a common phenomenon in germanic languages, german is special because of its rich inventory of linking elements: -e, -en, -ens, -er, -es, -n, -ns, -s, and -i/-o. furthermore, deletion and substitution may occur. whether the number of linking elements can be diminished by assuming variation similar to the allomorphic variation of the homophoneous inflectional affixes (e.g. -(e)n) is a disputed topic (cf. @xcite @xcite . the rules governing linking element selection are anything but obvious, even native speakers of german are sometimes unsure of the "correct" choice. linking elements also constitute a major challenge for natural language generation and machine translation (e.g. @xcite .. our study investigates a very specific linking strategy, which has received less attention so far: the deletion of a final schwa, in the literature sometimes referred to as subtractive linking element. an example for this strategy is endpunkt ('endpoint') which combines ende ('end') and punkt ('point'). though schwa-deletion in itself does not apply to too many words, it affects some high frequency nouns like sache ('thing', 'matter') and farbe ('colour', 'paint'). to explore the phenomenon systematically, we created a corpus of (almost) all simple nouns ending in schwa and asked two annotators to indicate the preferred linking strategy for each of those nouns. furthermore, we conducted a forced choice experiment to gain further insights. we report both studies in turn. ## linking element selection in german it is consensus that the choice of linking element is mainly determined by the left constituent in a compound. evidence comes from tupels like tag-e-buch 'diary', lit. 'day book', kind-er-buch 'children's book', jugend-buch 'book for adolescents', liebling-s-buch 'favorite book', schul-buch (schule+buch) 'school book' which share the second constituent but differ in the first constituent and the linking element. further evidence comes from coordinated compounds, such as gesundheits-und sozialwesen 'health care and welfare system'. expanding this conclusion, @xcite proposed that the lexical representations of nouns includes specific stems for compounding. notably, there a several cases that weaken this proposal as they exhibit variation within a single noun, e.g. tag-e-buch 'diary', tagtraum 'day dream', tag-es-satz 'daily rate' or beere-n-schnaps 'berry liquor' and blaubeer-schnaps 'blue berry liquor'. arguably, though, some of the variation can be explained with reference to diachrony, e.g. through fossilised forms. however, in the present paper, we focus on the role of the left constituent. there is less consensus about the function of linking elements (for a critical overview see neef 2015) and the conditions on le selection for a given noun as the first constituent in a compound, but see @xcite and @xcite for comprehensive overviews of morphophonological factors. for nouns ending in a schwa, the following descriptive generalisations have been hypothesised. feminine nouns as well as masculine nouns with weak declension pattern almost obligatorily take -n as the linking element, cf. @xcite , @xcite . schwa-deletion occurs rarely, but for some nouns regularly, cf. @xcite . schwa is never deleted when it constitutes a suffix, cf. @xcite . previous studies examined the distribution of linking elements across the board, i.e. for all kinds of nouns and all kinds of linking elements, by counting the occurrences in compounds in text corpora (e.g. @xcite or lexical resources like celex (e.g. @xcite ). the present study in contrast focuses on a particular type of left constituent, namely nouns ending in schwa. in this sense the present study is more limited; at the same time, it is more comprehensive since the corpus we present below captures virtually all nouns of this specific type. ## corpus study there is no resource one could use to look up compound strategies of german nouns. we therefore created a new corpus, focusing on items that could in principle make use of schwa-deletion. the entire corpus can be found at: https://gitlab.com/superpumpie/schwa_deletion . ## production experiment the lack of effective predictors and the dominance of -n suggest that n-insertion could be a form of default strategy for nouns ending in schwa. under this view, -n should also predominate in the absence of lexical information, and schwa-deletion would be an exception that is lexically encoded. if so, compounding of nonce words ending in schwa should apply n-insertion as the linking strategy. to test this prediction, we conducted a forced choice experiment with nonce words. in contrast to @xcite , who used existing words as the first constituent and nonce words as the second constituent (e.g. suppe 'soup' + fend), we use nonce words as the first constituent and combine them with an existing word. items were created with a script using python (python software foundation, 2018), all having the following syllable structure: one or more consonants, followed by a vowel or diphthong, followed by one or more consonants, plus a final schwa. examples include trulve and knüpse. we manually checked the list for phonological and graphematic well-formedness and excluded items that were phonologically or orthographically too close to existing words. from the remaining set, we randomly sampled 16 items and varied their gender in a within-items design. we created two lists such that each list contained each item in one of its two versions (fem. or masc.) and an equal number of fem. and masc. critical items. in addition, each list contained 8 real nouns ending in schwa (4 fem., 4 masc., all the same in both lists), as well as 24 fillers, both nonce and real nouns not ending in a schwa. using prolific ( https://www.prolific.co ), we recruited 24 native speakers of german. participants were requested to choose a linking element for compounding our experimental items with beschreibung ('description'). the words were presented with the corresponding article to indicate the gender (e.g. der knüpse + die beschreibung). participants could choose between 7 response categories: null (concatenation without an le), +e, +er, +n, +s, schwa-deletion, and "others". in total, we collected 304 data points for the critical nonce items. the data reveal a striking discrepancy between the distribution in the corpus of existing nouns ending in a schwa and the nonce words we tested in the experiment (figure 1 ). n-insertion as a default strategy would have predicted that almost all nonce words select that strategy. however, this is not the case. compared to the corpus data, the -n strategy is less prevalent in nonce compounding. these surprising findings challenge the idea of -n as a default strategy for nouns ending in schwa. assuming that linking strategies are encoded lexically, e.g. in form of specific compositional stems as part of the lexical representations of the nouns (cf. fuhrhop 1996), could explain both the lack of a consistent default strategy observed with the nonce words and the failure of the lme model on the corpus data to explain a great deal of the variance. ## concluding remarks while many linking elements in german are well-researched, the phenomenon of schwa-deletion is still an open question. the present paper explores the phenomenon in greater detail, by approaching it in various ways. however, the results of all our approaches paint a picture that is complex. a first analysis provides some probabilistic tendencies -pointing towards a predominance of paradigmatic linking elements. a linear mixed effects model could not identify a set of critical factors, though. the machine learning models that we trained also return poor results. and the results of the production experiment were also complex, hinting at the possibility that there is no default strategy. a plausible interpretation of all our approaches is that the choice of strategy is often encoded lexically. we hope that the results and the provided resources will be a starting point for further research and insights. 1