Këkkytir wrote: ↑Mon Nov 25, 2019 3:40 pmUnder what realistic conditions can fricatives become related stops (or nasals)? Examples: f → p, s → t, x → k. I want to get rid of most of the fricatives in my conlang somehow but I was told that an unconditional change into stops is very unlikely.
You can get away with it, particularly with intermediate steps, which Pabappa gave some examples of. One other possibility would be for the fricatives to become affricates, then stops (f > pf > p, etc.). Although you said you wanted it to be unconditional, if you wanted to go this route you might want to have them become affricates only in certain environments--say, after short vowels, fricatives lengthen, and then [f:] > [pf] (> [p]), etc., which could result in some fun alternations you could play with, if you wished. (And you could get rid of the remaining fricatives in other ways.)
Këkkytir wrote: ↑Mon Nov 25, 2019 3:40 pmSuppose that I want to introduce voicing contrast, but only for a few specific consonants. Would it make sense to turn an aspiration contrast into a voicing contrast? For example: t~d → d, t
h~d
h → t ? Are there other good ways to introduce voicing contrast but only for a few select consonants?
A change of an aspiration to a voicing contrast is definitely plausible, yes. (Though keep in mind that "voiced aspirates" aren't actual aspirates--except in a couple languages in uhhh Sarawak or something, where they're [bp
h]--they're breathy-voiced stops. So I would just say t, t
h > d, t. [Greek did turn breathy voiced consonants into voiceless aspirates, of course--probably--so you can have that as an intermediate step if your language has distinctive breathy voice already.] But the pathway you seem to be laying out of it beginning with optional and later obligatory voicing of original voiceless unaspirated stops, which makes the aspiration on the aspirated stops secondary/superfluous and thus either optional or eventually lost, is a good way to go about it.)