Dial *121*7*3# Download Free Bengali Learning App. http://bit.ly/AdarshaBanglaLipi Airtel Bangladesh (016) Dial *121*6*3# Grameenphone (017) Dial *2# BanglaLink (019) Dial *511# Teletalk (015) Dial *551# Robi (018) Dial *140*2*4# Or, Dial 1200 and listen and then choose option 4