The language, when it's non-vegetarian food! (6)
I believe the answer is:
tongue
'the language' is the definition.
(tongue can mean a language)
'when it's non-vegetarian food' is the wordplay.
I cannot quite see how this works, but
'when' could be 'on' (I've seen this in other clues) and 'on' is found within the answer.
'food' could be 'e' (E is an example) and 'e' is found in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'gu' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tongue that I've seen before include "Mouth organ; language" , "Projecting strip" , "rudely, one could be put out" , "Part of shoe or mouth" , "Perhaps the Gaelic" .)