The most common and most likely answer to this crossword clue is the 12 letter word SPOKESPERSON
I've seen this crossword clue in The Daily Telegraph
S
P
O
K
E
S
P
E
R
S
O
N
Buddy explains!
The straight part
We know that "who has something to say" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case who has something to say = spokesperson.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 SPOKESPERSON mean?
SPOKESPERSON noun- A person who acts as the voice of a group of people.