language vs discussion

language and discussion both are nouns.

Word	Noun	Adjective	Verb	Adverb
language	Yes	No	No	No
discussion	Yes	No	No	No

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

language (noun)	discussion (noun)
the mental faculty or power of vocal communication	an exchange of views on some topic
the cognitive processes involved in producing and understanding linguistic communication	an extended communication (often interactive) dealing with some particular topic
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