Variability in the clear speech intelligibility advantage
Kenneth Konopka, Rajka Smiljanić, Ann R. Bradlow · The Journal of the Acoustical Society of America · 2005
The overall intelligibility advantage for sentences produced in clear versus conversational speech is well-documented. This study looked at recognition accuracy across words in early and late positions in semantically anomalous and meaningful sentences spoken in clear versus conversational speaking styles. For both sentence types, the results showed the expected overall intelligibility advantage for clear speech over conversational speech. For the semantically anomalous sentences, in both speaking styles, a decline in keyword identification rate was observed with words earlier in the sentence being more accurately recognized than words later in the sentence. Furthermore, the intelligibility advantage for clear over conversational speech remained relatively constant across word positions. For the meaningful sentences, the decline in keyword identification rate across word positions was observed for conversational speech only. Meaningful sentences spoken in clear speech yielded a high, relatively stable word identification rate across position-in-sentence, resulting in a larger clear speech intelligibility benefit for words late in the sentence than for words early in the sentence. These results suggest that for typical meaningful sentences, the acoustic-phonetic enhancements of clear speech and the availability of semantic-contextual information combine to ‘‘boost’’ the intelligibility of words in late sentence positions.