The most common and most likely answer to this crossword clue is the 11 letter word PRELITERATE
I've seen this crossword clue in Financial Times
P
R
E
L
I
T
E
R
A
T
E
Buddy explains!
The straight part
We know that "without as yet any developed written language" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case without as yet any developed written language = preliterate.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 PRELITERATE mean?
PRELITERATE noun- A member of such a culture
- (of a culture) that has not yet developed a written language
- (of a person) who has not yet learned to read and write