The most common and most likely answer to this crossword clue is the 4 letter word ERSE
I've seen this crossword clue in The Guardian
E
R
S
E
More clues leading to the result ERSE
- Irish poetry needing no introduction
- Language writer seldom uses
- Language Beardsley uses occasionally
- Essentially disregarding Patel’s first language
- Gossiper seldom bites tongue
- Language in Poetry: volume missing
- Old language in newspaper, Serbian
- Lexicographer seeking to preserve minority language
- Conversed in old language? Just the opposite
- 7 composition not beginning in language of 29?
Buddy explains!
The straight part
We know that "old language" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old language = erse.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.