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Mixed effects regression models are widely used by language researchers. However, these regressions are implemented with an algorithm which may not converge on a solution. While convergence issues in linear mixed effects models can often be addressed with careful experiment design and model building, logistic mixed effects models introduce the possibility of separation or quasi-separation, which can cause problems for model estimation that result in convergence errors or in unreasonable model estimates. These problems cannot be solved by experiment or model design. In this paper, we discuss (quasi-)separation with the language researcher in mind, explaining what it is, how it causes problems for model estimation, and why it can be expected in linguistic datasets. Using real linguistic datasets, we then show how Bayesian models can be used to overcome convergence issues introduced by quasi-separation, whereas frequentist approaches fail. On the basis of these demonstrations, we advocate for the adoption of Bayesian models as a practical solution to dealing with convergence issues when modeling binary linguistic data.

In the Spanish of north-western Spain, word-final /-d/ shows a remarkable variety of phonetic outcomes. Its possible realizations include voiced approximants, voiceless fricatives and voiced and voiceless plosives, in addition to the deletion of the segment. Here we examine this complex pattern of allophony in a corpus of conversational speech, focusing on the effect of the following phonological context. The results show that most commonly /-d/ is either deleted or realized as a voiceless fricative. Voiceless fricatives are found in all phrasal contexts, but with significantly higher frequency before pause than before a vowel, which is consistent with the hypothesis of diachronic extension of the devoicing from the former context to the latter. The devoicing of /-d/ is neutralizing. Voiceless fricative realizations of /-d/ do not differ from those of phonemic /-θ/ either in amount of voicing or in duration. This implies that deletion and devoicing represent two alternative patterns of reduction starting from [ð], since phonemic /-θ/ is not subject to deletion. Whereas the deletion of /-d/ has lexical exceptions, its devoicing does not. Among the majority of /d/-final words, for which deletion is possible, the relative frequency with which they undergo deletion vs. devoicing appears to vary substantially depending on the specific lexical item. That is, both position in phrase and lexical identity probabilistically determine the realization of /-d/. In addition to contributing to our understanding of the synchronic and diachronic phonology of word-final obstruents in Spanish, we consider the extent to which these data, showing variable word-final devoicing, may help us understand the historical evolution of the crosslinguistically common phenomenon of systematic word-final devoicing.

Since Bolinger's [1] discovery that pitch cues accentual prominence in English, a tension has arisen between two strategies: equating accent with pitch excursions and relying on perception for identifying accented words. This paper investigates the relation between prominence judgments from untrained listeners and accentual labels produced by trained transcribers. Naïve speakers of English, Spanish and French (30 per language) were asked to mark prominent words in excerpts of conversational speech from their native language (between 900-1100 words in each sample). Aggregated prominence scores (P-scores) were compared with experts' ToBI labels for each language. For all three languages, words ToBI-labelled as accented had substantially higher P-scores than unaccented words, and nuclear accents had higher Pscores than prenuclear ones. P-scores also discriminated among several accent types. Predictions from prior research on the relative prominence of accent labels were tested, and findings confirm that English L+H* accents are more likely to be judged as prominent than H* accents, and Spanish L+H* is more likely judged as prominent than L+>H*. However, for French, our prediction that Accentual Phrase-initial Hi is prominence-lending was not confirmed. The results establish the link between tonal accents and perceived prominence in three languages that differ in their use of contrastive prominence at the lexical and phrasal levels..