Speech rate

Tempo of speech, expressed in e.g words per minute or syllables per second. Variations in speech rate may be caused either by variations in pause rate (slower speech involves more pausing), or by variations in articulation rate (the speed with which the syllables themselves are produced, regardless of pauses in between the words), or by both. Articulation rate is therefore the more accurate measure if one is interested in the segmental characteristics of fast speech.

Links
Utrecht Lexicon of Linguistics