An acoustic investigation of the developmental trajectory of lexical stress contrastivity in Italian

• We examined whether Italian children exhibit adult-like stress contrastivity in their production of polysyllabic words.
• Most of our normalised acoustic measures of vowel duration, intensity, and fundamental frequency showed that children's stress contrastivity was adult-like.
• However, for trisyllabic words beginning with a weak–strong pattern children exhibited less stress contrastivity than adults in terms of vowel duration.
• Differences in gemination between children and adults may affect contrastivity for words beginning with a weak–strong pattern.
• Results discussed as language-specific versus physiological motor-speech constraints.

We examined whether typically developing Italian children exhibit adult-like stress contrastivity for word productions elicited via a picture naming task (n = 25 children aged 3–5 years and 27 adults). Stimuli were 10 trisyllabic Italian words; half began with a weak–strong (WS) pattern of lexical stress across the initial 2 syllables, as in patata, while the other half began with a strong–weak (SW) pattern, as in gomito. Word productions that were identified as correct via perceptual judgement were analysed acoustically. The initial 2 syllables of each correct word production were analysed in terms of the duration, peak intensity, and peak fundamental frequency of the vowels using a relative measure of contrast—the normalised pairwise variability index (PVI). Results across the majority of measures showed that children's stress contrastivity was adult-like. However, the data revealed that children's contrastivity for trisyllabic words beginning with a WS pattern was not adult-like regarding the PVI for vowel duration: children showed less contrastivity than adults. This effect appeared to be driven by differences in word-medial gemination between children and adults. Results are compared with data from a recent acoustic study of stress contrastivity in English speaking children and adults and discussed in relation to language-specific and physiological motor-speech constraints on production.