An IPA/Chao tone letter will rarely be composed of more than three elements (which are sufficient for peaking and dipping tones). Occasionally, however, peaking–dipping and dipping–peaking tones, which require four elements – or even double-peaking and double-dipping tones, which require five – are encountered. This is usually only the case when prosody is superposed on lexical or grammatical tone, but a good computer font will allow an indefinite number of tone letters to be concatenated. The IPA diacritics placed over vowels and other letters have not been extended to this level of complexity.
