Upstep

Upstep is a phonological phenomenon in which the pitch of a high tone (H) on a following syllable is raised relative to the preceding high tone, usually across a boundary within a tonal language. It commonly occurs when a low tone (L) intervenes between two high tones: the second high is realized at a higher pitch than the first, producing an upward reset in the tonal sequence. This contrasts with downdrift or downstep, where subsequent highs are lowered or gradually lowered across the utterance.

Analyses of upstep often invoke frameworks such as autosegmental phonology or intonational phonology, treating upstep as a contextual allophone of the high tone caused by the presence of a low tone, a boundary, or a process that resets pitch height. The exact phonetic realization can vary by language and context; in some languages the effect is phonemic, contributing to lexical contrasts, while in others it is a phonetic or phonotactic cue at a prosodic boundary.

Upstep is a specialized concept within the study of tonal systems and intonation. It is distinct from simple pitch movement in non-tonal languages and from focal or expressive pitch movements; it is defined by a systematic, language-specific raising of subsequent high tones in particular contexts. The phenomenon is observed in the literature on tonal languages and is used to study pitch control, tonal alignment, and the interaction of tone with syntax and discourse.