vox vs sprechstimme

vox and sprechstimme both are nouns.

Word	Noun	Adjective	Verb	Adverb
vox	Yes	No	No	No
sprechstimme	Yes	No	No	No

As nouns, sprechstimme is a hyponym of vox; that is, sprechstimme is a word with a more specific, narrower meaning than vox:

vox: the sound made by the vibration of vocal folds modified by the resonance of the vocal tract
sprechstimme: a style of dramatic vocalization between singing and speaking

Other hyponyms of vox include singing voice, sprechgesang, voice over, voice.

vox (noun)	sprechstimme (noun)
the sound made by the vibration of vocal folds modified by the resonance of the vocal tract	a style of dramatic vocalization between singing and speaking