Dissimilation is a phonological process that involves one of two similar or identical sounds within a word becoming less like the other or even disappearing entirely. Because r’s in successive syllables are particularly difficult to pronounce, they frequently dissimilate. One historical example of dissimilation is marble, from French marbre. In this case the second r has dissimilated to l in order to prevent a repetition of the r and ease articulation. Other contemporary examples of dissimilation include enterprise, governor, impropriety, prerogative, surprise, and thermometer, in which there is a tendency for the first r to drop out of the pronunciation resulting in (n´t-prz´´), (gv´-nr), (m´´p-pr´-t), (p-rg´-tv), (s-prz´), and (th-mm´-tr). None of these examples really receives any adverse criticism, but some instances of dissimilation may, as the pronunciation (l´br´´) for library. Note that other consonants besides r may be altered or omitted as a result of dissimilation, such as n in government (gv´r-mnt).
n´t
-pr
z´´), (g
v´
m´´p
), (p
g´
