[Nero_3D]

pawn Code:

//OnPlayerText
static stext[MAX_PLAYERS][128];
if(!strfind(text, stext[playerid], true))
  return SendClientMessage(playerid, 0xFFFFFFAA, "Don't Repeat yourself!"), false;
format(stext[playerid], sizeof stext[], text);

if you type

hello
hello -> "Don't Repeat yourself!" and dont sends the hello in public

or

hello
hellottt -> "Don't Repeat yourself!" and dont sends the hellottt in public