Tone (linguistics) - Register Tones and Contour Tones

Register Tones and Contour Tones

Tone systems fall into two broad patterns, according to whether contour tones exist.

Most Chinese languages use contour tone systems, where the distinguishing feature of the tones are their shifts in pitch (that is, the pitch is a contour), such as rising, falling, dipping, or level. Most Bantu languages, on the other hand, have non-contour tone (or register tone) systems where the distinguishing feature is the relative difference between the pitches, such as high, mid, or low, rather than their shapes. In such systems there is a default tone, usually low in a two-tone system or mid in a three-tone system, that is more common and less salient than other tones. There are also languages that combine relative-pitch and contour tones, such as many Kru languages, where nouns are distinguished by contour tones and verbs by pitch. Others, such as Yoruba, have phonetic contours, but these can easily be analysed as sequences of single-pitch tones, with for example sequences of high–low /áà/ becoming falling, and sequences of low–high /àá/ becoming rising .

Falling tones tend to fall further than rising tones rise; high–low tones are common, whereas low–high tones are quite rare. A language with contour tones will also generally have as many or more falling tones than rising tones. However, exceptions are not unheard of; Mpi, for example, has three level and three rising tones, but no falling tones.

Lexical tones more complex than dipping (falling–rising) or peaking (rising–falling) are quite rare, perhaps nonexistent, though prosody may produce such effects. However, the Old Xiang dialect of Qiyang is reported to have two "double contour" lexical tones, high and low fall–rise–fall, or perhaps high falling – low falling and low falling – high falling: ˦˨˧˨ and ˨˩˦˨ (4232 and 2142).