Spontaneous laughter produced by two subjects was analyzed and compared to speech, measurements of both temporal and spectral characteristics being made. Speech and laughter were found to be quite similar in "syllable" duration and in the number of syllables per second. However, timing within syllables differed markedly. Fundamental frequency and rms amplitude of the laughter were also rather speech-like, although some extremes were observed. Formant structure of the laughter was also similar to speech. Bandpass filtering in the region of the third formant, however, showed the vocalic portions to include significant amounts of noise and breathiness, implying a more abducted vocal-fold configuration in the vocalic portions for laughter.