@WeedLikeToSmoke With GSC you can do it, you need to use also the feddd plugin
#include maps\mp_utility;
#include common_scripts\utility;
#include maps\mp\gametypes_hud_util;
init()
{
onPlayerSay(::callbackPlayerSay);
}
callbackPlayerSay(text, mode)
{
// mode == 0 -> all
// mode == 1 -> team
// self -> player that sent the message
self tell("You are not allowed to type in the chat");
return false;
}