Such patterns are found in the Dene (Athabaskan) languages such as Navajo (Young and Morgan 1987, McDonough 2003), Tahltan (Shaw 1991), Western Apache, and in Chumash on the California coast (Applegate 1972, Campbell 1997).
The following examples are given by de Reuse: in Western Apache, the verbal prefix si- is an alveolar fricative, as in the following forms: However, when the prefix si- occurs before a verb stem that contains a post-alveolar affricate, the si- surfaces as the post-alveolar shi-: Thus, all sibilant obstruents (fricatives and affricates) in these languages are divided into two groups, +anterior (s, ts, dz) and -anterior (sh, ch, j).
Young and Morgan (1987) offer an extensive sets of examples of this type of morpheme alternation in Navajo.
The retroflexion spreads from left to right affecting any coronal nasal until the word boundary is reached.
According to modern reconstructions of Old Chinese phonology, type A and B syllables almost never co-occur in a disyllabic word.
[2] However, there are notable, though infrequent, exceptions to this tendency, manifesting in ancient compounds that are generally hard to analyze.
Some Finnish-speakers find it hard to pronounce both 'b' and 'p' in loanwords (pubi, pub) and so they voice (bubi) or devoice (pupi) the entire word.