Cantonese changed tones occur when a word's tone becomes a different tone due to a particular context or meaning. A "changed" tone is the tone of the word when it is read in a particular lexical or grammatical context, while the base tone is usually the tone of the word when read in citation. It is thus distinct from tone sandhi, which are automatic modifications of tone created by their phonetic environment, without regard to meaning. In its most common form, it occurs on the final syllable of either a compound word, a reduplicated word, or certain addressive examples, especially in direct address to people such as family members. There are a limited set of semantic domains where changed tone occurs, generally associated with small things, familiarity, food and disease.