speaking vs public speaking

speaking and public speaking both are nouns.

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

As nouns, speaking and public speaking are synonyms defined as:

speaking and public speaking: delivering an address to a public audience

Other synonyms of speaking include oral presentation, speechmaking.

speaking (noun)	public speaking (noun)
delivering an address to a public audience	delivering an address to a public audience
the utterance of intelligible speech

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