- *l > /r/ (found in Indo-Iranian languages)
- *n > /r/ (found in Albanian)
- *ð > /r/ (found in Ostrobothnian Finnish)
- *z > /r/ (in the history of the Italic languages, Germanic languages, according to some proposals Turkic languages, and several others)
- *ɣ > /r/ (found in Western Daju languages)
Rhotacism is often an unconditional sound change.
A change to a flap such as /ɾ/ is, however, usually not called rhotacism, but flapping. It is also commonly restricted to intervocalic or medial positions. Flapping usually affects stops such as /d/ (for example American English), or laterals such as /l/ (for example Norwegian).