Language used by parliament on Guernsey (6)

I believe the answer is:

tongue

'language' is the definition.
(tongue is a kind of language)

'used by parliament on guernsey' is the wordplay.
'used by' says the answer is hidden in the clue.
'TONGUE' is hidden within 'parliament on guernsey'.

(Other definitions for tongue that I've seen before include "Mouth organ; language" , "They are hard to say" , "Speech" , "cold meat?" , "manner of speaking" .)

I've seen this clue in The Telegraph.

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