language vs mental lexicon

language and mental lexicon both are nouns.

Word	Noun	Adjective	Verb	Adverb
language	Yes	No	No	No
mental lexicon	Yes	No	No	No

language (noun)	mental lexicon (noun)
the mental faculty or power of vocal communication	a language user's knowledge of words
the cognitive processes involved in producing and understanding linguistic communication
a systematic means of communicating by the use of sounds or conventional symbols
(language) communication by word of mouth
the text of a popular song or musical-comedy number
a system of words used to name things in a particular discipline