I am wondering how the two phonological terms "morphonemic rules" and "morphophonemic rules" can be distinguished?
A morpheme might have different presentations (i.e. pronunciations) and as far as I know, morphonemic rules are utilized in order to specify different phones (pronunciations / realizations) of that particular phoneme.
The plural /s/ sounds [z], whenever a noun ends in anything else than <+sibilants> or <-voice> segments.
According to what we were taught at the university, this is considered to be a morphonemic rule, but what are morphophonemic rules?