speaking vs vocalization

speaking and vocalization both are nouns.

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

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

Other hypernyms of speaking include utterance.

speaking (noun)	vocalization (noun)
delivering an address to a public audience	the sound made by the vibration of vocal folds modified by the resonance of the vocal tract
the utterance of intelligible speech	the use of uttered sounds for auditory communication

speaking (adjective)	vocalization (adjective)
capable of or involving speech or speaking
capable of speech