Assimilation is said to have taken place when one speech segment is transformed into another owing to the influence of a neighboring segment. In the majority of cases the segments are individual speech sounds but there are instances where a whole syllable will influence a neighboring syllable. There are also instances where the neighboring segment is, in fact, not a speech sound at all but the silence that follows a syllable (see ‘Word-final De-voicing’ in Voicing Change).
Assimilatory processes may be sorted into different types. If the segment causing assimilation is immediately next to affected segment, then this is known as contiguous assimilation. In contrast, if the segment causing assimilation is not next to affected segment then this is non-contiguous assimilation. In addition, if the affected segment follows the segment causing assimilation this is referred to as progressive assimilation. The opposite situation, where the affected segment precedes the segment causing assimilation is known as regressive assimilation. These types are summarized in Table 13.
Table 13. Types of assimilation.
As with substitution, several types of assimilation are identifiable. In this subsection we will describe three of these:
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