The most common and most likely answer to this crossword clue is the 5 letter word LINGO
I've seen this crossword clue in The Times
L
I
N
G
O
More clues leading to the result LINGO
- Shortening piece of verse, try peculiar vocabulary
- Language used by girl in Gothenburg
- One piercing awfully long tongue
- Fish served with duck's tongue
- Language assimilated by pupil in Gordonstoun
- . Stumbling over nursing jargon
- Text shortened, depart peculiar vocabulary
- Baffling old cases that can be hard to interpret
- Language used in Berlin government
- Particular speech from Dublin gobshite
Buddy explains!

The straight part
We know that "tongue" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tongue = lingo.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 LINGO mean?
LINGO noun- Language, especially language peculiar to a particular group, field, or region; jargon or a dialect.