The most common and most likely answer to this crossword clue is the 8 letter word LINGUIST
I've seen this crossword clue in Financial Times
L
I
N
G
U
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S
T
More clues leading to the result LINGUIST
- Fish by Scottish island, one with many tongues?
- One skilled in words banishing guilt and sin
- Language master resorts to Latin initially, using it in translation
- Six ducks living on Scottish islands, one with more than one tongue
- Language master demands Latin, initially — and using it in translation!
- One using Latin? Using it in translation
- One many-tongued, fantastic unicorn’s skin is gilt
Buddy explains!

The straight part
We know that "Language master" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case language master = linguist.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 LINGUIST mean?
LINGUIST noun- One who studies linguistics.
- A person skilled in languages.
- A human translator; an interpreter, especially in the armed forces.