POC for detecting native PlayerSay calls and fowarding them to EasyChat's own networking (only works in sandbox derived gamemodes).

easychat_native_playersay_calls.lua

--[[
	---------------------------------------------------------------------
		THIS ONLY WORKS IN SANDBOX, DARKRP DOES WEIRD STUFF WITH ITS
	 	GAMEMODE PLAYERSAY HOOK SO IT WONT WORK (SAME WITH MURDER)
	---------------------------------------------------------------------
--]]

hook.Add("PostGamemodeLoaded", TAG, function()
	local existing_callbacks = hook.GetTable().PlayerSay or {}
	for identifier, callback in pairs(existing_callbacks) do
		hook.Remove("PlayerSay", identifier)
		hook.Add("ECPlayerSay", identifier, callback)
	end

	hook.NativeAdd = hook.NativeAdd or hook.Add
	function hook.Add(event_name, ...)
		if event_name == "PlayerSay" then
			event_name = "ECPlayerSay"
		end

		hook.NativeAdd(event_name, ...)
	end

	hook.NativeCall = hook.NativeCall or hook.Call
	function hook.Call(event_name, ...)
		if event_name == "PlayerSay" then
			event_name = "ECPlayerSay"
		end

		return hook.NativeCall(event_name, ...)
	end

	-- handle messages that are run by the engine (usually the say or say_team commands)
	hook.NativeAdd("PlayerSay", TAG, function(ply, msg, is_team, is_local)
		if not IsValid(ply) then return end -- for console just let source handle it I guess

		EasyChat.ReceiveGlobalMessage(ply, msg, is_team, is_local or false)
		return "" -- we handled it dont network it back the source way
	end)

	-- make the default behavior follow the gamemode PlayerSay one
	function GAMEMODE:ECPlayerSay(ply, msg, is_team, is_local)
		return self:PlayerSay(ply, msg, is_team, is_local)
	end
end)