Tone sandhi

Tone sandhi occurs to some extent in nearly all tonal languages, manifesting itself in different ways.

However, African languages frequently exhibit downdrift and mobility, forms of tone interaction.

[2] Southern Min (Minnan), which includes Hokkien, Taiwanese, and Teochew, has a complex system, with in most cases every syllable changing into a different tone, and which tone it turns into sometimes depending on the final consonant of the syllable that bears it.

In Taiwanese, within a phonological phrase, all its non-neutral-tone syllables save for the last undergo tone sandhi.

In a language of the right-dominant system, the right-most syllable of a word retains its citation tone[a].

[citation needed] Tone sandhi is compulsory as long as the environmental conditions that trigger it are met.

For example, Cantonese has a derivational process known as changed tone, which only applies in certain semantic domains.

[citation needed] Standard Chinese (Standard Mandarin) features several tone sandhi rules: Yatzachi Zapotec, an Oto-Manguean language spoken in Mexico, has three tones: high, middle and low.

A number of specific rules depending on these three factors determine tone change.

Specifically, sandhi rules may target classes of phones not previously identified as natural, the conditioning environments may be disjoint, or the tone substitutions may occur without any reason.

This is because waves of sound change have hidden the original phonetic motivation of the sandhi rule.