Three important strands of research characterise modern phonological theory; (i) the cyclic interaction of morphology and phonology; (ii) prosodic structure as it is built from segments into moras, syllables, feet and ultimately the phonological word; and (iii) the precise internal structure of segments, including feature geometry, how these features may reside on autosegmental tiers, and how they may be underspecified.

Over the last few years, much work in phonology has been devoted to exploring the way features are specified for segments; in particular, to what extent feature specification may be underlyingly present and/or acquired by rule or default in the course of a derivation. While a number of proposals have been made attributing various degrees of underspecification to abstract levels of the phonology (Kiparsky 1985; Steriade 1987; Archangeli 1988), it has been generally assumed that where phonetic implementation comes into play, i.e. at the end of the derivation, segments are exhaustively specified.

An important contribution to our knowledge of tone sandhi among the Chinese dialects is Lü's (1980) article on the tones and tone sandhi behaviour of Danyang, a Wu dialect of Chinese. Lü's description of Danyang is, to date, our only source on the dialect. While it is a northern Wu dialect, the tone sandhi patterning in Danyang differs from Shanghai, Suzhou, Wuxi and other dialects in the vicinity. There are a number of interesting problems related to tone in the dialect. This paper restricts the topic to only one of these problems, namely the treatment of the six basic tone patterns in Danyang, focusing in particular on the pattern in which a contour tone is copied Onto adjacent syllables in the tone sandhi domain.

A basic assumption in current phonology is that features are not an unstructured set like (1a), but are arranged hierarchically into a constituent structure tree such as (1b), proposed in Sagey (1986: 61):

Other groupings of features have been proposed (Clements 1985; Steriade 1987; inter alii).

A fundamental assumption of theories like (1b) is that rules operate on constituents, an assumption which is formalised by limiting rules to spreading or delinking a single node.

The functional equivalence of CVV and CVC syllables, as opposed to CV syllables, is a time-honoured observation holding true for numerous languages over a variety of phonological and morphological phenomena, including stress assignment (cf. Newman 1972 for a review). Traditionally, the opposition between the two types of syllables has been informally described by reference to syllable weight: CVV and CVC syllables are heavy, CV syllables are light (e.g. La Grasserie 1909: 31–32). It has also been observed, however, that in languages sensitive to the CV/CVV distinction, CVC syllables do not necessarily pattern with CVV syllables, but may instead pattern with CV syllables, thus counting as light rather than heavy (Hyman 1985: 5–6; McCarthy & Prince 1986: 32–34; Hayes 1989: 255–256).