Culminativity of tone: Culminativity means that there can be, at maximum, only one toneme (underlying tone) per word. Culminativity does not require every word to have a toneme; a system can be regarded as culminative even if there are toneless words.
Downdrift and downstep: Downdrift is a spontaneous lower realization of H or M after a L. Downstep, in most cases, is a lowering of a non-initial H if preceded by a floating L, in the context H!H. In some languages, the (non-automatic) downstep it is also possible between two M or L. (In Stewart’s terms, downdrift = downstep, and downstep = non-automatic downstep.)
Floating tone is a toneme or a component of toneme which is not associated with any segment at the underlying level.
Obligatoriness of tone: The obligatoriness means that any word form bears at least one toneme, or it is included into a tonal span of a neighbouring word.
Tonal density is expressed in the Tonal Density Index (TDI) which equals the number of tonemes per 100 syllables (or morae). More details here.
Tonal level is a distinctive pitch range relevant for the tonal system.
Tonal melody is a tonal contour of underspecified phonological status.
Tonal phrase: A syntactic construction including more than one tonal
Tonal span: a segment associated with a toneme on the surface level. More details here.
Tone is used:
- in an abstract sense: Tone is a system of linguistic oppositions based on the pitch difference (e.g., “language X has tone”);
- in a specific sense: Tone is a tonal contour (tonal level or melody) of underspecified phonological status.
Toneless syllable (or TBU) can be of two types. Underlyingly toneless syllables/TBU: if a tonal domain extends to more than one TBU, it can be said that the toneme is associated with the first one, and the other TBUs are underlyingly toneless; superficially toneless TBUs: they remain extratonal superficially. More detail here.
Toneme: a meaningful tone, i.e. a tone which can (potentially) distinguish lexical and/or grammatical meanings. More details here.
Zero tone is a default tone which has no status of toneme in a language.