language vs textual matter

language and textual matter both are nouns.

Word	Noun	Adjective	Verb	Adverb
language	Yes	No	No	No
textual matter	Yes	No	No	No

As nouns, textual matter is a hypernym of language; that is, textual matter is a word with a broader meaning than language:

Other hypernyms of language include text.

language (noun)	textual matter (noun)
the mental faculty or power of vocal communication	the words of something written
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