Age and Rhtymic Variations: A study on Italian

Age-related variations in the speech production mechanism affecting acoustic cues such as pitch, speech rate, formant frequencies have been extensively investigated. Changes in speech rhythm and in utterance composition in terms of vowel and consonant portions are, instead, scarcely examined. Given the relevance of the vowel percentage (%V) in the utterance and of the interval between two vowel onset points (VtoV) for the perception of language rhythm, this study aims to investigate the relationship between rhythmic variations and speaker age. It also attempts to determine whether %V can be affected by different speech rates. Four young adult and four old speakers of Italian read four sentences of different length, at four different speech rates. The whole corpus was segmented in vocalic and consonantal portions and in VtoV intervals. The analysis results have shown that aged voice accompanies with significant increase in %V, despite speech rate variations. With advancing age, Italian speech tends to shift from the isosyllabic towards the isomoraic rhythmic pattern.