This paper describes the acoustic characteristics of hesitations in Estonian spontaneous speech. We especially investigate duration, fundamental frequency, and first two formant analyses. Most frequent hesitations can be expressed by lengthened phonemes such as /ää/, /ee/, /õõ/, and /mm/. We compare lengthened phoneme hesitations with their related phonemes. The results from our preliminary hesitation study show (i) hesitations have longer duration and its range is spread; (ii) hesitations globally include lower pitch; (iii) hesitation formants are likely to be centralized or posterior and opened in comparison with related phonemes.

Index Terms: hesitation, Estonian, spontaneous speech