Language quickly penetrated by husband (6)
I believe the answer is:
apache
'language' is the definition.
(Apache is an example)
'quickly penetrated by husband' is the wordplay.
'quickly' becomes 'apace' (synonyms).
'penetrated by' means one lot of letters goes inside another (I've seen this in other clues).
'husband' becomes 'h' (abbreviation).
'apace' placed around 'h' is 'APACHE'.
(Other definitions for apache that I've seen before include "settler in Oklahoma?" , "on the streets of Paris" , "ruffian in capital of France" , "Parisian gangster" , "Native American - French hoodlum" .)