walk-on vs nonspeaking

walk-on is a noun but nonspeaking is not a noun.

Word	Noun	Adjective	Verb	Adverb
walk-on	Yes	Yes	No	No
nonspeaking	No	Yes	No	No

As adjectives, walk-on and nonspeaking are synonyms defined as:

walk-on and nonspeaking: not capable of or especially not involving speech or spoken lines

walk-on (noun)	nonspeaking (noun)
plays a small part in a dramatic production

walk-on (adjective)	nonspeaking (adjective)
not capable of or especially not involving speech or spoken lines	not capable of or especially not involving speech or spoken lines