speaking vs susurration

speaking and susurration both are nouns.

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

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

Other hyponyms of speaking include speech, voicelessness, whisper, whispering, voicelessness.

speaking (noun)	susurration (noun)
delivering an address to a public audience	speaking softly without vibration of the vocal cords
the utterance of intelligible speech	the indistinct sound of people whispering

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