A cross-linguistic examination of toddlers' interpretation of vowel duration

Abstract

Languages differ in their phonological use of vowel duration. For the child, learning how duration contributes to lexical contrast is complicated because segmental duration is implicated in many different linguistic distinctions. Using a language-guided looking task, we measured English and Dutch 21-month-olds' recognition of familiar words with normal or manipulated vowel durations. Dutch but not English learners were affected by duration changes, even though distributions of short and long vowels in both languages are similar, and English uses vowel duration as a cue to (for example) consonant coda voicing. Additionally, we found that word recognition in Dutch toddlers was affected by shortening but not lengthening of vowels, matching an asymmetry also found in Dutch adults. Considering the subtlety of the crosslinguistic difference in the input, and the complexity of duration as a phonetic feature, our results suggest a strong capacity for phonetic analysis in children before their second birthday.

Keywords: language acquisition; phonetics; phonology; speech perception; word recognition.

Figure 1.

Dutch children’s target fixation proportions when hearing words that normally have long vowels (left panel) or short vowels (right panel). Responses to correct pronunciations (CP) are darker bars, mispronunciations (MP) lighter ones. Subject means are shown for percentage to target (where chance is about 50%) and for this percentage less each child’s “salience” score for the target picture (so chance is about 0%; see text). Individual child means for each condition are given as dark linked dots. Error bars are standard errors of the mean.

Figure 2.

American children’s target fixation proportions when hearing words that normally have long vowels (left panel) or short vowels (right panel). Responses to correct pronunciations (CP) are darker bars, mispronunciations (MP) lighter ones. Subject means are shown for percentage to target (broad bars) and for this percentage minus each child’s “salience” score for the target picture (narrower, darker bars). Individual child means for each condition are given as dark linked dots. Error bars are standard errors of the mean.

Figure 3.

For each child, the difference between his or her mean target fixation on correct-pronunciation trials and target fixation on mispronunciation trials. The left panel shows performance for words with canonically long vowels; the right panel words with canonically short vowels. Means and standard errors are shown with open circles and error bars.