Using phonological neighborhood density has been a common method to quantify lexical competition. It is useful and convenient but has shortcomings that are worth reconsidering. The present study quantifies the effects of lexical competition during spoken word recognition using acoustic distance and acoustic absement rather than phonological neighborhood density. The indication of a word’s lexical competition is given by what is termed to be its acoustic distinctiveness, which is taken as its average acoustic absement to all words in the lexicon. A variety of acoustic representations for items in the lexicon are analyzed. Statistical modeling shows that acoustic distinctiveness has a similar effect trend as that of phonological neighborhood density. Additionally, acoustic distinctiveness consistently increases model fitness more than phonological neighborhood density regardless of which kind of acoustic representation is used. However, acoustic distinctiveness does not seem to explain all of the same things as phonological neighborhood density. The different areas that these two predictors explain are discussed in addition to the potential theoretical implications of the usefulness of acoustic distinctiveness in the models. The present paper concludes with some reasons why a researcher may want to use acoustic distinctiveness over phonological neighborhood density in future experiments.
Voiceless nasal consonants are typologically rare in the world’s languages. The present study investigates the acoustic realization of reported voiceless nasals in the Miyako Ryukyuan dialect Ikema. Voiceless nasals in Ikema occur word-initially and word-medially as part of a geminate or consonant cluster, and are phonemically distinct from modal voiced nasals. Initial observation of collected recordings revealed many instances of the voiceless phoneme with voicing throughout, leading to a re-evaluation of previous claims about its phonetic implementation. We hypothesized that word-medial and phrase-medial voiceless nasals surface as breathy voiced nasals. We analyzed the acoustic characteristics of nasal components of target words, focusing on duration, phonation state, and cepstral peak prominence (CPP), to determine whether reported voiceless nasal phonetic components with voicing are acoustically distinct from modal voiced nasal consonants. We find that voiceless nasals are produced with a voiceless component followed by a modal voiced component. Voiceless components and breathy components are found to be significantly shorter than modal components. We also find a significant difference between modal nasal, breathy nasal and voiceless nasal components’ CPP values. The results confirm the observation that Ikema voiceless nasals are phonemically distinct from modal nasal consonants, and likely allophonically vary with breathy voiced nasals word-medially and phrase-medially. These findings align with the hypothesis that voiceless nasals require some voicing to be audible for perception, and are consistent with cross-linguistic findings, contributing to the typological understanding of the acoustics of voiceless nasals.
The present study investigates and compares the acoustic characteristics of uh [ə] and um [əm] spontaneous speech. The data comes from a corpus of Western Canadian conversational spontaneous speech. Measures of duration, fundamental frequency, F1 and F2 were extracted from 1,048 instances of um and uh. Results indicate that longer durations occurred when markers preceded silent pauses. Um was found to have higher F1 and lower F2 than uh. F0 was overall lower for um in comparison to uh. These results provide a preliminary understanding of um and uh as markers in spontaneous Canadian English. Canadian English shows a similar proportion of um over uh usage in comparison to American and British English. Findings on vowel duration show no significant difference between um and uh. Differences in f0, F1 and F2 provide additional indication of how um and uh are different.
Multiple measures of vowel overlap have been proposed that use F1, F2, and duration to calculate the degree of overlap between vowel categories. The present study assesses four of these measures: the spectral overlap assessment metric [SOAM; Wassink (2006). J. Acoust. Soc. Am. 119(4), 2334–2350], the a posteriori probability (APP)-based metric [Morrison (2008). J. Acoust. Soc. Am. 123(1), 37–40], the vowel overlap analysis with convex hulls method [VOACH; Haynes and Taylor, (2014). J. Acoust. Soc. Am. 136(2), 883–891], and the Pillai score as first used for vowel overlap by Hay, Warren, and Drager [(2006). J. Phonetics 34(4), 458–484]. Summaries of the measures are presented, and theoretical critiques of them are performed, concluding that the APP-based metric and Pillai score are theoretically preferable to SOAM and VOACH. The measures are empirically assessed using accuracy and precision criteria with Monte Carlo simulations. The Pillai score demonstrates the best overall performance in these tests. The potential applications of vowel overlap measures to research scenarios are discussed, including comparisons of vowel productions between different social groups, as well as acoustic investigations into vowel formant trajectories.