Full text
| |
| Author(s): |
Larissa Mary Rinaldi
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Estudos da Linguagem |
| Defense date: | 2010-08-26 |
| Examining board members: |
Eleonora Cavalcante Albano;
Regina Yu Shon Chun;
Ivone Panhoca
|
| Advisor: | Eleonora Cavalcante Albano |
| Abstract | |
This master's thesis study aims at creating a reference database for the study of vowels and obstruents in child speakers of Brazilian Portuguese (henceforth BP). The subjects are between 5 and 7 years old, with no history of speech disorders. Special tool was developed for data collection, centered on a child story named "Fairy Tales Go Crazy" with 57 words created for the instrument with all sounds of BP in initial and medial onset position. To prompt word utterance a board game was used. The total number of target words is only 36: total of words which were created by matching each BP obstruent (fricatives and plosives) with the vowels [a], [i] and [u]. The tool was used in this study to observe obstruents and vowels only in initial stressed position. The data was collected from 9 children (5 girls and 4 boys) in the final stages of language acquisition, selected as randomly as possible. Researcher asks each child to say the target words embedded in a carrier sentence. A preliminary analysis showed that acoustic phonetic parameters were not always sufficient to describe the variation and dynamics of the speech signal in child language. Therefore, we have used two types of analysis: a Static Acoustic Analysis and a Dynamic Acoustic Analysis. The static acoustic analysis made the following measurements: for vowels, relative duration (a percent obtained of segment absolute duration divided per word duration), absolute duration and the first three formants; for fricatives, relative and absolute duration and the four spectral moments (Jongman, 2000). The fricative spectral moments were measured at their center in a 40 millisecond window; for plosives, relative and absolute duration, voice onset time (VOT) and the burst spectral moments (Forrest et al., 1988). Statistical analysis was performed by a General Linear Model (GLM) with a Repeated Measures Analysis of Variance. Alpha was set at 0.05. For the vowels the dependent variables were the formants and the independent ones were the vowels. As expected, F1 was effective in differentiating the vowel [a] from [i] and [u], F2 was effective for differentiating the three vowels, F3 was effective only to differentiate the vowel [i] from [u] and [a]. For the fricatives the independent variables were the articulation places (lip-dental, alveolar or post-alveolar) associated with the voicing (voiced or devoiced) - total of six independent variables - and the dependent variables were the first four spectral moments. The skewness and centre of gravity were effective in differentiating the three places of articulation, and the association between the voicing and place. The kurtosis did not distinguish fricatives in any parameter. The standard deviation differed only place of articulation. For plosives the independent variables were places of articulation (bilabial, dental/alveolar and velar) associated with the voicing (voiced or devoiced) - total of six independent variables - and the dependent variables were the four spectral moments and VOT. The skewness and centre of gravity were effective in differentiating the three places of articulation, the voicing and the association between voicing and place. The kurtosis and variance were effective in differentiating the three places of articulation and voicing separately, but not for their association. As expected, the VOT could distinguish the voicing, but was also effective for differentiating the place of articulation as well as the association between voicing and point. The dynamic acoustic analysis showed that voiced plosives may devoice and devoiced plosives may voice. It showed that, often, normal children's strategies are similar to those with language pathologies described by Berti (2006), Freitas (2007) and Rodrigues (2007). We should note that none of these phenomena would seem strange to the adult listener, being auditorily imperceptible. In spite of deviating from adults in acoustic trajectories as seen on spectrograms, normal children seem to produce something which sounds close to what is expected by adults. These phenomena may be illuminated by Gestural Phonology (Browman & Goldstein, 1992; Ball & Kent, 1997; Scobbie, 1998; Albano, 2001; Kent & Read , 2002; Shadle, 2006; Goldstein, Byrd & Saltzman 2006). We hope this approach may shed further light on this work (AU) | |