Evidence of a Production Basis for Front/Back Vowel Harmony Jennifer Cole, Gary Dell, Alina Khasanova University of Illinois at Urbana-Champaign Is there a functional basis for certain commonly observed linguistic sound patterns? Are phonological constraints innate or learned from primary speech experience? Is there a special status for sound patterns that facilitate the acts of speaking and comprehension? How phonological constraints might impact speech: reduce articulatory complexityincrease perceptual salience optimize lexical accessoptimize speech planning Possible functional bases for vowel harmony perceptual: assimilatory sound patterns may result from listeners’ “misperception” of coarticulated vowel sequences (Ohala 1993; Beddor et al 1999). Vowel harmony may thus reduce perceptual ambiguity. articulatory: the occurrence of shared features/gestures increases articulatory economy (Lindblom 1983). speech planning: repeating phonological structure facilitates speech planning, as structures are ‘recycled’ in the planning of successive chunks of speech. Our Hypothesis: Vowel harmony, where vowel features are shared across successive vowels, may result in an economy of speech articulation or planning, manifesting in speech that is faster and/or less errorful. Sevald et al (1995) find that subjects produce sequences of nonsense syllables faster when the syllables have a common syllable structure, despite differences in the segmental content of those syllables. They attribute this effect to an economy at the level of speech planning. Testing the hypothesis with fast speech experiments Experiment I: Front/Back Vowel Harmony Method: Subjects repeat sequences of nonsense syllables as many times as possible in five seconds, while maintaining accuracy in pronunciation. Nonsense syllables are presented on a computer screen in a sequence on a single line of text. The subject rehearses the sequence aloud once or twice and is prompted to begin producing the fast repeated speech at the sound of a tone. Another tone signals the end of the trial. Subjects: 26 monolingual native English users, undergrads at UIUC from the Chicago area, with self-reported normal speech and hearing. Materials: Nonsense sequences of the form CVCV the CVCV. C was selected from /b,g,k/. V was selected from /i:, u:, e:, o:/, phonetically [ij, uw, ej, ow]. The two vowels within each CVCV word were distinct. Example, presented orthographically: beeboo the baybo The harmony condition: sequences where each CVCV word contained only front /i:, e:/ or only back /u:, o:/ vowels, e.g., beebay the boboo, or boboo the boobo. The four sequences of identical vowels were excluded from the study (e.g., beebee). Total number of harmonic CVCV-CVCV sequences: (4x1x4x1) vowel sequences = 16; 16 x 3 consonants = 48. The disharmony condition: sequences where each CVCV word contained vowels that disagreed in their front/back feature, e.g., bobee the boobee. Total number of disharmonic CVCV-CVCV sequences: (4x2x4x2) vowel sequences = 64. These were divided into 4 groups of 16, each balanced for frequency of individual vowels and vowel combinations. Subjects were quasi-randomly assigned to each disharmony group. Total disharmonic CVCV-CVCV sequences per set: 16 x 3 consonants = 48. Both words in a sequence were in the same harmony condition; there were no harmonic-disharmonic mixed sequences. The materials set was balanced for the occurrence of each vowel individually, and for vowel combinations within the word. Coding: Speech data was recorded onto tape and coded for errors and number of syllables per trial by two independent coders. Coder agreement was 90.58% and highly correlated (R 2 =.951). Data from two subjects was eliminated due to error rates over 50%. Analysis: 1-tailed t-tests were used to compare mean syllable production times and mean error rates for harmonic and disharmonic conditions within each consonant condition. Mean syllable production time based on production time for error-free trials: 5000 ms./ # of syllables. Mean error rate, as a percent of total trials. Results: Experiment 1, Front/Back Harmony 1.Mean production times are significantly lower in the harmony condition with the consonant /b/ (t=1.865, p< 0.05). 2.Mean error rates are significantly lower in the harmony condition with all consonants: /b/ (t=1.721, p<0.05), /k/ (t=3.089, p<0.01) and /g/ (t=1.877, p<0.05). Conclusion: Front/Back vowel harmony facilitates fast speech production, reducing the incidence of errors. Is this an effect on speech articulation or speech planning? Hypothesis: If vowel harmony facilitates speech planning, similar facilitation effects should be observed for vowel harmonies involving different vowel features. Experiment II: Height Vowel Harmony Method and subjects same as Experiment I. Materials: nonsense sequences of the form CVd.hVd the CVd.hVd, with V chosen from the set of lax vowels / ,  / (high) and / ,  / (non-high), and C chosen from /b,k,g/. Tense vowels were rejected to avoid the height contour of the tense diphthongs [ej, ow]. Harmonic sequences: e.g., goodhid the gedhud (hi-hi – nonhi-nonhi) Disharmonic sequences: e.g., bedhood the bidhud (nonhi-hi – hi-nonhi) Results: No harmony effects observed in production times or error rates. Conclusion: the failure of height harmony to reduce errors in fast speech suggests that the harmony effect observed with back/front harmony is specific to that dimension of vowel articulation. Together, these findings suggest that vowel harmony reduces the complexity of speech articulation, and does not result in a general facilitation of speech planning. Implications for speech planning : facilitation effects occur only with shared structural features (e.g., syllable or metrical structure), but do not extend to shared features of segment quality. References: Beddor, P., Krakow, R. and S. Lindemann Patterns of perceptual compensation and their phonological consequences. In E. Hume and K. Johnson (eds.), The Role of Speech Perception in Phonology, pp New York: Academic Press. 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