Intonation patterns of Black English were studied and compared with those occurring in White English and formal Black English. It was found that: (1) the Black English corpus was characterized by a wider pitch range, extending into higher pitch levels than either the White vernacular or the formal Black English of the adult information; (2) a falsetto register was used in Black English more often than either White English or formal Black English; and (3) more rising and level final contours were used in Black English, while White English and formal Black English used more falling final contours. This study provides evidence, never previously reported, of the use of intonation alone in Black English to serve a grammatical function of marking the dependent clause of a conditional sentence, without concomitant use of the lexical item "if". It is concluded that intonation cannot be studied apart from the social situation. The majority of the intonational characteristics found in the Black English corpus can be traced directly to systematic differences between black street culture and white "mainstream" culture, rather than to any systematic differences in phonology per se, and may be accounted for as resulting from different "social rules" for speech with black street culture. (Author/LG)