This paper compares the acoustic differences in spontaneous recordings of child and adult laughter. Results indicate that, mean pitch and intensity of laughter are significantly different in adults and children but they follow expected speech patterns. Children also have higher vocal tract resonant frequencies when compared to adults. However, both groups were similar in differentiating the non-phonated consonantal segment in laughter from the phonated vocalic segment through supralaryngeal dynamics. Consonants were produced with a lower jaw and forward tongue position with the jaw and tongue moving upwards and back respectively for the vowel. Finally, in this study laughter vowels fell within the Peteson and Barney speech vowel data but the spread was large not indicative of a reduced vowel status for laughter vowels.

Index Terms: child laughter, adult laughter, acoustic analysis