sprechstimme vs vocalism

sprechstimme and vocalism both are nouns.

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

As nouns, vocalism is a hypernym of sprechstimme; that is, vocalism is a word with a broader meaning than sprechstimme:

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

Other hypernyms of sprechstimme include phonation, vocalisation, vocalization, voice, vox.

sprechstimme (noun)	vocalism (noun)
a style of dramatic vocalization between singing and speaking	the sound made by the vibration of vocal folds modified by the resonance of the vocal tract
	the system of vowels used in a particular language