Wikipedia =/= 100% accurate
Especially if its not written by experts,
Except that
it is. Everything on Wikipedia is validity checked.
It generally takes the form of a cylindrically shaped metal tube with various internal mechanisms to reduce the sound of firing by slowing the escaping propellant gas and sometimes by reducing the velocity of the bullet.[1][2]
A silencer slows down the bullet, to make the Soundbreaker bang stop.
It decreases the velocity of the bullet trivially, but that's only because it makes the barrel longer (increasing friction). The suppressor works on the exploding gases, and moves them around to reduce and
scatter the sound caused by the expanding gases. You said it slows down the bullet to a subsonic speed and that's ridiculous. There's such thing as subsonic ammo, but you said the suppressor does that, and that's untrue.