This third article in a series presenting the results of a computer-assisted analysis of a vast data file, based on recordings of upper middle-class Parisian conversations, deals with syllabic rate and utterance length. Performance standards are established for teaching, linguistic theory and voice-processing technology. Variations in these aspects of speech are studied as functions of a number of demographic, psychological, intellectual and phonetic background parameters. Syllabic rate is found to vary as a function of sex, age, occupation and certain intentions, while utterance length varies as a function of age, occupation, certain intentions, certain attitudes and loudness. Overall rate averages turn out to be strikingly consistent, most speakers showing about 344 syll/min. Finally, a positive correlation exists between utterance length and syllabic rate; the longer the utterance, the faster the rate and vice versa. A hypothesis is suggested that these results reflect language universals.