Cantonese changed tones (also called pinjam;^[1] traditional Chinese: 變音; simplified Chinese: 变音; pinyin: biànyīn; Jyutping: bin3jam1; Cantonese Yale: binyām) 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 (or underlying) tone is usually the tone of the word when read in citation.^[2] 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 vocative examples, especially in direct address to people such as family members.^[2] There are a limited set of semantic domains where changed tone occurs, generally associated with small things, familiarity, food and disease.^[3]

A changed tone usually takes the form of a non-high level, non-mid rising tone (i.e. tones 3, 4, 5, and 6 in Jyutping and Yale; see Cantonese phonology for further information on the tones in Cantonese) transforming into a mid-rising tone (tone 2); for some speakers, this changed tone is slightly lower than the citation mid-rising tone.^[1]

In other lexemes, the tone of the last syllable becomes a high level tone (tone 1 in Yale and Jyutping). This is especially true if the penultimate syllable already has tone 1 as its citation tone.^[2] For speakers with the high falling tone, this may also become the high level tone via the same process.^[1]

In many speakers, another form of a changed tone used in specific vocatives that may also result in a high level tone (tone 1), rather than in a mid-level tone.^[4]

Taishanese also exhibits changed tones. It is realized in some cases as an additional high floating tone to end of the mid level, low level, mid falling and low falling tones; this results in new contours for Taishanese, namely mid rising, low rising, mid dipping and low dipping respectively. The final pitch of these changed tones may be even higher in pitch than the citation high level tone. Another changed tone occurs where the expected tone is replaced by the low falling tone. These two are combined in certain cases, with the result that the expected tone is replaced by the low dipping tone, such as the change of the verb 刷 /tʃat˧/ "to brush" into the noun 刷 /tʃat˨˩˥/ "a brush".^[5]

The use of a high rising tone in marking changed tone in many Yue varieties of Chinese implies one possible origin in diminutive morphemes, much in the same way that erhua functions in Standard Mandarin and in the Beijing dialect. In Cantonese, several diminutive morphemes have been proposed as the original one, among them 兒 /jiː˥/ "son" (in its high level tone form) and 子 /t͡siː˧˥/ "child". Thus the changed tone is the relic of the contraction of the main syllable with this diminutive.^[1]

A separate tone change that operates on verbs has also been attested, marking the perfective aspect. This is phonetically equivalent to the tone change above in Hong Kong and Guangzhou Cantonese, including the modification for those with a high falling tone.^[6]

This is believed to be the result of the merger of the perfective marker 咗 /t͡sɔː˧˥/ into the verb, and is thus also found in other Yue varieties, such as the dialect of Xiaolan in Zhongshan; it is also found in Hakka Chinese varieties, such as some varieties in Heyuan in northern Guangdong, as well as in Shicheng and Yudu in southern Jiangxi.^[7] This tone morpheme is even said to predominate over the overt perfective markers in certain areas such as Zhaoqing, Xinhui, Foshan and Shunde, giving rise to a form of tonal ablaut, although this is associated with the speech of the older generation.^[7]