Prosodic disambiguation of noun/verb homophones in child-directed speech.
Erin Conwell
PMID 26932727WHAT IT FOUND
Mothers' speech to children made noun and verb uses of the same word sound different, but only when the word came in the middle of the utterance.
At sentence ends, those acoustic clues disappeared.
Key findings
01Noun uses were longer than verb uses in middle positions, and their vowels were longer too.
02The same duration differences were not found in sentence-final positions.
03Verb uses had larger vowel formant ratios than noun uses in middle positions, but not in final positions.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The findings came from six mother-child pairs, so they may not represent all families or all speech styles. The study analysed speech recordings only; it did not show what children heard, understood, or learned from these differences. The acoustic differences were found mainly in middle-of-utterance uses, so they may not apply to words at the end of sentences. The pitch results are less clear: the model tests did not show a main effect of lexical category on pitch change, although the summary reported greater pitch change for noun tokens. The paper did not compare child-directed speech with an equivalent adult-directed spontaneous corpus, so differences from adult speech cannot be confirmed.
The easy way to misread this
Do not conclude that these prosodic differences show how children learn noun and verb categories or that a therapy can use them to improve word learning. The study measured mothers' speech only, and it did not test child outcomes.