1. Go to 'cstrike/addons/amxmodx/configs' and open the config file 'grenade_callouts.ini' on Notepad.
2. Copy the texts below and replace the FIRST 9 LINES in the config file with the copied texts. Save and exit.

Flashbang out!
Throwing flashbang!
Flashbang!
Fire in the hole!
Grenade out.
Grenade!
Smoke.
Throwing smoke.
Covering with smoke.