Comparisons of the temporal patterns of pairs of syllables differing only as to presence versus absence of a particular consonant suggests that the temporal effect of the consonantal articulation is not necessarily either additive or simply related to the duration of the acoustic segment conventionally associated with the consonant. In a study of such temporal effects, various monosyllables were embedded in turn in a short carrier sentence, and each version of the sentence was read 30 times at a carefully controlled tempo by one speaker. Durations of segments, syllables and breath‐groups were measured from oscillograms, and least pairs, e.g.,sayversusslay, compared. It appears that final stop or final nasal lengthens both syllable and breath group by an amount roughly equal to the durations of the corresponding acoustic segment; an initial stop, liquid or aspirate induces no appreciable lengthening, other segments in the syllable being sharply reduced; and initial /s/ lengthens the syllable breath group by an amount approaching the duration of the fricative segment the durations of the other acoustic segments being slightly reduced. It is hoped that these results will contribute to more adequate synthesis by rule. [Work supported by NIH and VA.]