Tone plays a critical role in Northern Wu and impacts the realisation of both initials and finals. It disambiguates between both monosyllabic words via underlying tone and polysyllabic terms through the use of tone sandhi. Northern Wu languages can theoretically have up to twelve
phonemic tones, depending on analysis. These lects can be found in places in
Suzhou and
Jiaxing, such as
Wujiang.
Phonemic tone Phonemic tones in Northern Wu is traditionally analysed based on
four historical tone categories, which are further divided in half based on the
voicing of the initial. Those that pair with voiceless initials are known as "dark" () tones and the opposite is true for "light" () ones. This yields a total of eight tones. The hypothetical maximum of 12 tones are achieved when
aspiration conditions a further tone split through the dark tones. Note that, unlike
Yue languages, the dark checked tone split is conditioned by aspiration, not
vowel length. Although there are Northern Wu lects with a high number of tones, it is also noteworthy that contemporary
Shanghainese in particular only has at most five phonemic tones, by merging tones 2 and 4 with 6, and tones 3 with 5. A typical Northern Wu variety has 7–8 tones. For the most part, light tones can only occur with voiced initials, and dark tones can only occur with voiceless initials. In general, the light counterpart of a dark tone tends to be a lowered (or depressed) equivalent of the dark tone, as explored above. Compare the pronunciations of the dark and light departing tones in the following Wu varieties:
Neutral tones Neutral tones (), informally transcribed as 0 or not transcribed at all, are found in tone sandhi and in some grammatical particles. For instance, the perfective particle in Shanghainese should be tone 8 due to its voiced and checked nature, though it in reality functions without a tone. This phenomenon can also be observed in
Standard Mandarin, though it is more pronounced in Northern Wu due to the grammatical nature of Northern Wu sandhi.
Tone sandhi Northern Wu languages all have
tone sandhi, both left-prominent (hereafter LPS) and often right-prominent (RPS). LPS is typically found in polysyllabic words, whereas RPS is typically found in verb-object constructions. This is a feature that is shared among Wu languages, though in Northern Wu, sandhi chains generally share similar contours. This, coupled with the fact that this sort of complex tone sandhi cannot be found in the
Qieyun system or reconstructions of
Middle Chinese, would suggest that this sandhi is a Wu shared innovation, and that Northern Wu languages share a recent common origin. There are five general types of contours: • Contour spreading, where the contour of the head syllable gets stretched over subsequent syllables • Default realization, where the subsequent syllables become null tones • Contour leveling, where a syllable removes its tone contour movement such that it becomes level • Citation target, where a tone on a syllable in a sandhi chain varies compared to its monosyllabic/citation form because it is affected by other conditioning factors such as stress. For example, stress can cause an apparent tone contour to start and end higher compared to its underlying form. Stress can also neutralize the dipping portion of such a bidirectional tone, becoming a simple rising contour (if the underlying tone is low-dip-high ˨˩˦). • Categorical shift, where the subsequent syllables change tone categories
Left-prominent sandhi LPS in Northern Wu is typically regarded as highly complex. Northern Wu varieties are traditionally analysed to have unique sandhi chains for each tone category of every syllable, which results in complex charts that sprawl several pages. However, these analyses can usually be simplified, and not all combinations yield unique sandhi chains. Shanghainese LPS, for instance, has traditionally been analysed to only preserve phonemic tone on the first or head syllable, and drop it on all subsequent syllables, which may thus be considered somewhat similar to
pitch accent in some languages. However, some younger speakers insert a rising tone contour on traditionally voiced initials to perhaps mimic the depression effect. This is similar to some analyses of
Suzhounese and
Hangzhounese. Checked tones in Suzhounese can be analysed to preserve the underlying tone of the first two syllables, whereas Hangzhounese sandhi is conditioned based on whether the second syllable belongs to the rising or non-rising category. The tone category of the third and fourth syllables do not matter.
Right-prominent sandhi RPS primarily occurs on verbs in verb-object constructions, and often is only relevant to monosyllables. They also occur in certain situations such as quantitative adjectives and a handful of irregular words. This can be used to disambiguate between certain constructions, such as the famous example, but also the following: == Notes ==