The most common and most likely answer to this crossword clue is the 9 letter word PROVENCAL
I've seen this crossword clue in The Times
P
R
O
V
E
N
C
A
L
More clues leading to the result PROVENCAL
- Successfully tested class, securing good grade in French language
- French national’s tried and tested state
- Demonstrated calibre briefly in French language
- Unruly clan, first to demonstrate in French region
- Established peace, banishing monsieur from a French region
- Established source of company’s aluminium in French region
- Frenchman’s confirmed short visit
- Ascertained state of a French region
- Shown around lake of French region
- Nice person beyond doubt, cares a lot at first …
Buddy explains!
The straight part
We know that "French language" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case french language = provencal.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.