sprechstimme vs vocalization

sprechstimme and vocalization both are nouns.

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

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

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

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

sprechstimme (noun)	vocalization (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 use of uttered sounds for auditory communication