The most common and most likely answer to this crossword clue is the 6 letter word ARGOTS
A
R
G
O
T
S
More clues leading to the result ARGOTS
Buddy explains!

The straight part
We know that "Languages" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case languages = argots.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.
What does ARGOTS mean?
ARGOTS noun- A secret language or conventional slang peculiar to thieves, tramps and vagabonds.
- The specialized informal vocabulary and terminology used between people with special skill in a field, such as between doctors, mathematicians or hackers.