Speak for itself/themselves
Definition 1 of 1
Pro Tip 1/3Impressive Results
Use when outcomes are so good, they don't need praise or commentary to be recognized. 
Her grades this semester speak for themselves.
Pro Tip 2/3Unspoken Proof
No need for additional evidence; the thing you're discussing proves its own worth. 
The turnout for the event speaks for itself.
Pro Tip 3/3Not Literal
It's a figurative expression; nothing is actually 'speaking.' It's about obvious implications. 
The silence from the critics speaks for itself.