In Nigerian Pidgin's simple tone system with derived complex tones, tones are used for both lexical and grammatical distinctions. There is basically a two-tone system plus a rare (in most cases post-lexical) downstepped high tone. Most lexical items have a single underlying tone that interacts with phrasal stress. Falling and rising contour tones occur as the result of the interaction between phrasal stress and tone (a stressed H becomes HL and a stressed L becomes LH). There is a large set of lexical items, all of which come from African languages, all of whose syllables are specified for tone underlyingly and none of which undergo any modification in pitch due to phrasal stress.