Andrea G. Levitt

The universality of intrinsic F0 of vowels

Abstract The tendency for high vowels such as [i] and [u] to have higher fundamental frequencies (F0s) than low vowels such as [a] has been found in every language so far in which it has been sought. This includes 31 languages representing 11 of the worlds 29 major language families (as defined by Crystal, 1987 ). While the size of the intrinsic F0 (IF0) effect varies from study to study, the differences seem to derive from differences in the study design, especially in the number of subjects. The effect appears larger for female speakers when expressed in Hz, but it is, instead, larger for males when the results are expressed in semitones. The size of the languages vowel inventory did not significantly affect the size of IF0. One other universal, though, is that the effect disappears at the low end of a speakers F0 range. The consistency of intrinsic F0 across languages argues that the effect is truly intrinsic; that is, it is not a deliberate enhancement of the signal but rather a consequence of successfully forming a vowel.

Intonational differences between the reduplicative babbling of French- and English-learning infants

The two- and three-syllable reduplicative babbling of five French-learning and five English-learning infants (0;5 to 1;1) was examined in two ways for intonational differences. The first measure was a categorization into one of five categories (RISING, FALLING, RISE-FALL, FALL-RISE, LEVEL) by expert listeners. The second was the fundamental frequency (F0) from the early, middle and late portion of each syllable. Both measures showed significant differences between the two language groups. 65% of the utterances from both groups were classified as either rising of falling. For the French children, these were divided equally into the rising and the falling categories, while 75% of those utterances for the English children were judged to have falling intonation. Proportions of the other three categories were not significantly different by language environment. In both languages, though, three-syllable utterances were more likely to have a complex contour than two-syllable ones. Analysis of the F0 patterns confirmed the perceptual assessment. Several aspects of the target languages help explain these intonational differences in prelinguistic babbling.

The roles of phoneme frequency, similarity, and availability in the experimental elicitation of speech errors ☆

Abstract In two experiments subjects read aloud pairs of nonsense syllables rapidly presented on a display screen or repeated the same syllables presented auditorily. The error patterns in both experiments showed significant asymmetry, thus lending support to explanations of the error generation process that consider certain phonemes to be “stronger” than others. Further error analyses revealed substantial effects of phoneme frequency in the language and effects of phoneme similarity, which depended on the feature system used to index similarity. Phoneme availability (the requirement that an intruding phoneme be part of the currently presented stimulus) was also important but not essential. We argue that the experimental elicitation of errors provides critical tests of hypotheses generated by the analysis of naturally occurring speech errors.

Perceptual assimilation and discrimination of non-native vowel contrasts.

Research on language-specific tuning in speech perception has focused mainly on consonants, while that on non-native vowel perception has failed to address whether the same principles apply. Therefore, non-native vowel perception was investigated here in light of relevant theoretical models: the Perceptual Assimilation Model (PAM) and the Natural Referent Vowel (NRV) framework. American-English speakers completed discrimination and native language assimilation (categorization and goodness rating) tests on six nonnative vowel contrasts. Discrimination was consistent with PAM assimilation types, but asymmetries predicted by NRV were only observed for single-category assimilations, suggesting that perceptual assimilation might modulate the effects of vowel peripherality on non-native vowel perception.

Assimilation of non‐native vowel contrasts to the American English vowel system.

The perceptual assimilation model (PAM) [Best et al., JEP:HPP 14, 345–360 (1988)] predicts that two non‐native sounds that are assimilated to the same nature category will be harder for listeners to discriminate between than sounds that are assimilated to two different native categories (TC contrasts); how difficult will depend on whether they are equally good (or bad) exemplars of the single native category (SC contrasts) or not (CG contrasts). PAM was based on studies of consonant perception, as were subsequent tests of the model. This study extends the model to non‐native vowels. American listeners performed keyword identification [W. Strange and T. L. Gottfried, J. Acoust. Soc. Am. 68, 1622–1625 (1979)] and categorical AXB discrimination tasks using six non‐native vowel contrasts, Norwegian /i–y/, /i–■/, French /o–o/, /œ–y/, /œ–■/, and Thai /■–■/. Assimilation patterns for a particular vowel contrast, inferred from keyword results, were more variable than in consonant studies but nonetheless strongly ...

Evidence for phonetic processing of cues to place of articulation: Perceived manner affects perceived place

Using stimuli that could be labeled either as stops [b,d] or as fricatives [f,v,θ,ð], we found that, for a given acoustic stimulus, perceived place of articulation was dependent on perceived manner. This effect appeared for modified natural syllables with a free-identification task and for a synthetic transition continuum with a forced-choice identification task. Since perceived place could be changed by changing manner labels with no change in the acoustic stimulus, it follows that the processing of the place feature depends on the value the listener assigns to the manner feature rather than directly on any of the acoustic cues to manner. We interpret these results as evidence that the identification of place of articulation involves phonetic processing and could not be purely auditor

Intrinsic F0 of vowels in the babbling of 6‐, 9‐, and 12‐month‐old French‐ and English‐learning infants

In every language so far examined, high vowels such as [i] and [u] tend to have higher fundamental frequencies (F0s) than low vowels such as [a]. This intrinsic F0 effect (IF0) has been found in the speech of children at various stages of development, except in the one previous study of babbling. The present study is based on a larger set of utterances from more subjects (six French- and six English-learning infants), at the ages 6, 9, and 12 months. It is found, instead, that IF0 appears even in babbling. There is no indication in these data of a developmental trend for the effect, and no indication of a difference due to the target language. These results support the claim that IF0 is an automatic consequence of producing vowels.

An Articulatory Phonology Account of Preferred Consonant-Vowel Combinations

Certain consonant/vowel combinations (labial/central, coronal/front, velar/back) are more frequent in babbling as well as, to a lesser extent, in adult language than chance would dictate. The “Frame then Content” (F/C) hypothesis (Davis & MacNeilage, 1994) attributes this pattern to biomechanical vocal-tract biases that change as infants mature. Articulatory Phonology (AP; Browman & Goldstein, 1989) attributes preferences to demands placed on shared articulators. F/C implies that preferences will diminish as articulatory control increases, while AP does not. Here, babbling from children at 6, 9, and 12 months in English, French, and Mandarin environments was examined. There was no developmental trend in CV preferences, although older ages exhibited greater articulatory control. A perception test showed no evidence of bias toward hearing the preferred combinations. Modeling using articulatory synthesis found limited support for F/C but more for AP, including data not originally encompassed in F/C. AP thus provides an alternative biomechanical explanation.

The Acquisition of Prosody: Evidence from French- and English-learning Infants*

The reduplicative babbling of five French- and five English-learning infants, recorded when the infants were between the ages of 7;3 months and 11;1 months on average, was examined for evidence of language-specific prosodic patterns. Certain fundamental frequency and syllable-timing patterns in the infants’ utterances clearly reflected the influence of the ambient language. The evidence for language-specific influence on syllable amplitudes was less clear. The results are discussed in terms of a possible order of acquisition for the prosodic features of fundamental frequency, timing, and amplitude.

Syllable-internal structure and the sonority hierarchy: Differential evidence from lexical decision, naming, and reading

Treiman (1983) and others have argued that spoken syllables are best characterized not as linear strings of phonemes, but as hierarchically organized units consisting of an onset (initial consonant or consonant cluster) and a rime (the vowel and any following consonants) and that the rime is further divided into a peak or nucleus (the vowel) and a coda (the final consonants). It has also been argued that the sonority (or vowel-likeness) of the consonant closest to the peak, which is a function of its phonetic class, may have an effect on the strength of boundaries determined by the hierarchical division of the syllable (e.g., Treiman, 1984). We examined the evidence for syllable-internal structure and for sonority in two experiments that employed visually presented stimuli and lexical decision, naming, and reading tasks. Our results provide support for the breakdown of the rime into a peak and a coda and for an effect of the sonority of the postvocalic consonant on that break. This pattern occurred only in our lexical decision tasks, so the effect is assumed to be postlexical. We did not find an effect of the onset-rime boundary, perhaps because of an unanticipated effect of word frequency. Our results are discussed in terms of phonological coding in short-term memory.