Articulation testing versus conversational speech sampling.

Detailed speech analyses were performed on data from 61 speech-delayed children assessed by both a standard articulation test and a conversational speech sample. Statistically significant differences between the articulation accuracy profiles obtained from the two sampling modes were observed at all linguistic levels examined, including overall accuracy, phonological processes, individual phonemes, manner features, error-type, word position, and allophones. Established sounds were often produced more accurately in conversational speech, whereas emerging sounds were often produced more accurately in response to articulation test stimuli. Error patterns involving word-to-word transitions were available only in the context of continuous speech. A pass-fail analysis indicated that the average subject would receive similar clinical decisions from articulation testing and conversational speech sampling on an average of 71% of consonant sounds. Analyses of demographic, language, and speech variables did not yield any subject characteristics that were significantly associated with concordance rates in the two sampling modes. Discussion considers sources of variance for differences between sampling modes, including processes associated with both the speaker and the transcriber. In comparison to the validity of conversational speech samples for integrated speech, language, and prosodic analyses, articulation tests appear to yield neither typical nor optimal measures of speech performance.