The most common and most likely answer to this crossword clue is the 6 letter word UTTERS
I've seen this crossword clue in The Daily Telegraph
U
T
T
E
R
S
More clues leading to the result UTTERS
- Pure soprano voices
- Declaims truest composition
- “21 down”, son says
- Speaks of total chaos at the back
- Speaks in murmurs leaving mass
- Delivers more than one golf club without head
- Says crazy people should be beheaded
- Lets out lunatics losing head
- Puts out and out and out, interminably so
- States eliminate source of murmers
Buddy explains!

The straight part
We know that "Speaks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case speaks = utters.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 UTTERS mean?
UTTERS verb- To produce (speech or other sounds) with one's voice.
- To reveal or express (an idea, thought, desire, etc.) with speech.
- To produce (a noise) (of an inanimate object).
- To spit or blow (something) out of one's mouth.
- To emit or give off (breath).
- To shed (a tear or tears).
- To offer (something) for sale; to sell.
- To put (currency) into circulation.
- To show (something that has been hidden); to reveal the identity of (someone).
- To send or put (something) out.