Fifteen caregivers each glossed a simultaneously videotaped and audiotaped sample of their child with speech delay engaged in conversation with a clinician. One of the authors generated a reference gloss for each sample, aided by (a) prior knowledge of the child's speech-language status and error patterns, (b) glosses from the child's clinician and the child's caregiver, (c) unlimited replays of the taped sample, and (d) the information gained from completing a narrow phonetic transcription of the sample. Caregivers glossed an average of 78% of the utterances and 81% of the words. A comparison of their glosses to the reference glosses suggested that they accurately understood an average of 58% of the utterances and 73% of the words. Discussion considers the implications of such findings for methodological and theoretical issues underlying children's moment-to-moment intelligibility breakdowns during speech-language processing.