Glottal Opening and Strategies of Production of Fricatives

International audienceThis work investigates the influence of the gradual opening of the glottis along its length during the production of fricatives in intervocalic contexts. Acoustic simulations reveal the existence of a transient zone in the articulatory space where the frica-tion noise level is very sensitive to small perturbations of the glottal opening. This corresponds to the configurations where both frication noise and voiced contributions are present in the speech signal. To avoid this unstability, speakers may adopt different strategies to ensure the voiced/voiceless contrast of frica-tives. This is evidenced by experimental data of simultaneous glottal opening measurements, performed with ePGG, and audio recordings of vowel-fricative-vowel pseudowords. Voice-less fricatives are usually longer, in order to maximize the number of voiceless time frames over voiced frames due to the crossing of the transient regime. For voiced fricatives, the speaker may avoid the unstable regime by keeping low frication noise level, and thus by favoring the voicing characteristic, or by doing very short crossings into the unstable regime. It is also shown that when speakers are asked to sustain voiced fricatives longer than in natural speech, they adopt the strategy of keeping low frication noise level to avoid the unstable regime

Do French-speaking learners simply omit the English /h/?

Intervention au séminaire "Recherches en Phonétique et Phonologie", Laboratoire de Phonétique et Phonologie (UMR7018).It is commonly considered that French-speaking learners of English tend to drop /h/. In such cases, a hard vowel onset is often observed, suggesting the presence of a glottal stop preceding the vowel, whereas [h] is characterised by an open glottis. First, recordings of the nursery rhyme "Humpty Dumpty" of 37 French students were acoustically analysed. The H2/H1 ratio (i.e. relative amplitude of the first two harmonics) at the onset of the first vowel in words beginning with /h/ was measured as an indication of voice quality. As expected, out of the 14 students who dropped /h/ at least once, 11 showed a higher H2/H1 ratio on average when /h/ was not pronounced. Second, glottal opening measurements were conducted on 9 test words beginning with /h/ or null consonant produced by a native speaker of French, using ePGG (external lighting and sensing photo-glottography). The results suggest more clearly than the H2/H1 ratio data that the glottis is closed when /h/ is dropped. The data comparison shows the advantage of articulatory measurements such as ePGG when acoustic data alone do not provide sufficiently clear information on certain articulatory phenomena such as glottal aperture

Do French-speaking learners simply omit the English /h/?

It is commonly considered that French-speaking learners of English tend to omit the voiceless "glottal fricative" /h/ (Ostiguy et al. 1996, among others). This type of consonant observed in different languages is actually best described as a voiceless approximant without any particular place of articulation, with the vocal folds apart (Ladefoged 1990). Halle and Stevens (1971) define it with the feature [+ spread glottis]. In observing cases where the English /h/ is "omitted" by a French-speaking learner, not only the absence of turbulent noise but another acoustic phenomenon is often observed, namely, a hard vowel onset, which suggests the presence of a glottal stop preceding the vowel. If a glottal stop is produced, the glottis is closed and therefore it is only natural that [h], pronounced with the glottis open, should not be articulated. Do French-speaking learners show this tendency systematically? A set of recordings of recitations of the nursery rhyme "Humpty Dumpty" was analysed. The speakers were 40 first-year students enrolled in LCA at Université Paris-Est Marne-la-Vallée in 2007-2008. The H2 (second harmonic) / H1 (first harmonic) ratio (difference of intensity in dB) at the onset of the first vowel in the word "Humpty" at the beginning of stanza was measured as an indication of voice quality. A comparison between cases where the initial /h/ was pronounced and where it was not shows that H2/H1 ratio is higher in the latter case, suggesting that the glottis was less open when /h/ was not pronounced. These findings suggest that those French-speaking learners who have difficulty producing /h/ show "wrong" articulatory gestures: tensing the vocal folds instead of relaxing them, closing glottis instead of opening it to allow the pulmonic air-stream necessary for [h]. Pronunciation activities involving relaxing movements (e.g. sigh) may help to raise learners' consciousness about these articulatory gestures