This paper reports the results of a study of the intonation of 18 Mandarin Chinese speakerslecturing in English. As a basis for the study, it is proposed that intonation be considered agrammar of cohesion in English discourse: Drawing from the intonational model ofPierrehumbert and Hirschberg (1990), it is argued that discrete morphemes of intonationcorrespond to the categories of cohesion in Halliday and Hasan's (1976) typology. Thestudy investigated the hypothesis that the nonnative speakers who were able to use the intonationsystem of English most effectively would score higher on a global language test. Using aComputerized Speech Lab to measure pitch, four aspects of intonation were averaged for eachspeaker: (a) the pitch difference between newly introduced content words and function words, (b)the use of high pitch at phrase boundaries to link related constituents, (c) the use of pitch todistinguish contrasting items from given items, and (d) the paratone or increase inpitch range at rhetorical junctures to signal topic shift. These four measures were chosen for theircontribution to the cohesion of the lectures. Multiple regression analysis indicates that the fourthintonation variable, the paratone, was a significant predictor of these subjects' English testscores. Examples are given of the other variables in context from both low- and high-scoringspeakers. It is emphasized that intonation is not only a stylistic component of accent but also ameaning-bearing grammatical system.