The most common and most likely answer to this crossword clue is the 9 letter word PREVERBAL
P
R
E
V
E
R
B
A
L
More clues leading to the result PREVERBAL
Buddy explains!

The straight part
We know that "not ready to speak" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not ready to speak = preverbal.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 PREVERBAL mean?
PREVERBAL noun- (grammar) A preverb.
- (child development) At an early stage of development in which one is not yet able to communicate by means of words.
- (of a part of speech) Occurring before the verb in a sentence or expression.