Why is there no з- prefix in Russian?

Question

All the other prefixes ending in с I can think of off the top of my head have a counterpart ending with з.

бес-/без-

ис-/из-

вос-/воз-

The version with с is used before voiceless consonants, and the version with з is used before vowels and voiced consonants.

бесполезный, безымянный, бездушный

исходить, изыди, изгой

воспевать, возобновить, возможно

But the с- prefix is used in all cases, although before voiced consonants it is often pronounced as /z/

сделать, сброд, сглаживание

Is there a linguistic or historical reason why this prefix seems to stand as an exception?

Answer 1

Prefixes in Slavic languages originated from the prepositions merged with the roots.

The old Slavic prepositions надъ, подъ etc. which ended with ъ, were merged before the fall of the reduced vowels so the vowel was kept, and you can still see it on its historical place before the roots starting with a yotized vowel: объятие.

When the reduced vowels fell, prononciation changed to agree the articulation of now adjacent consonants, but orthography did not reflect it. The words подътвердити, отъдавити (ъ was read as a really short ы) became подтвердить, отдавить etc, with impossible combinations of a voiced and voiceless consonant. The both consontants are now voiced or not according to the last one ([поттвердить], [оддавить]) but written the old way.

The prepositions ending in -с and -з (раз, из etc.), however, did not end with a vowel. The orthography reflected it from the beginning.

But the prefix с- originated from the preposition cѫ which never ended in -с. It ended with ѫ. This nasal sound after denasalization of the yuses had changed into y in nouns like сумерки, сутки and into ъ (which later fell) in verbs, and undergone the process described earlier. So this prefix does not change in writing, just as the prefixes not ending with -c/з don't.

The prepositions без and через (and the Church Slavonic borrowing чрез) merged much later than the others, so until the orthography reform of 1918, they were always written без-, чрез- and через-.