[...]
#define dcmd(%1,%2,%3) if (!strcmp((%3)[1], #%1, true, (%2)) && ((((%3)[(%2) + 1] == '\0') && (dcmd_%1(playerid, ""))) || (((%3)[(%2) + 1] == ' ') && (dcmd_%1(playerid, (%3)[(%2) + 2]))))) return 1
[...]

public OnPlayerCommandText(playerid, cmdtext[])
{
  dcmd(playsound, 9, cmdtext);
  return 0;
  [...]
}

[...]

dcmd_playsound(playerid, params[])
{
	new value;
	if (sscanf(params, "i", value)) SendClientMessage(playerid, 0xFF0000AA, "Usage: \"/playsound <Sound Id>\"");
    else
	{
		PlayerPlaySound(playerid, value,0.0,0.0,0.0);
		SendClientMessage(playerid, 0x00FF00AA, "Playing Sound...");
	}
	return 1;
}

[...]