Language in case where stormy weather penetrates shelter (8)
I believe the answer is:
legalese
'language in case' is the definition.
'legalese' can be an answer for 'language' (I have seen 'formal language' mean 'legalese' so perhaps 'language' could also mean 'legalese'). I am not certain of the 'in case' bit.
'stormy weather penetrates shelter' is the wordplay.
'stormy weather' becomes 'gales' (I can't justify this - if you can you should give a lot more credence to this answer).
'penetrates' means one lot of letters goes inside another.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'gales' inserted into 'lee' is 'LEGALESE'.
'where' is the link.
Can you help me to learn more?
(Other definitions for legalese that I've seen before include "formal language" , "it's hard for most to understand" , "barman's peculiar words" , "such language at the bar!" , "contract wording?" .)