Avoid using key-board, to stay with the edit mode.On your left is a chalk board, and right is a temp storage block, drag and drop enabled.Please note that using some keys(e.g. backspace) in the key board may stop showing the texts on the left pane; then copy the contents from the right pane and paste in the left. 

Bengali Key Board

--make compound word
Sample words
পশ্যৈতাং//ৈত //াং  কনস্ছানুরমর্দনম
To write শ্য় = First press , press then press  

ব, সব্যসাচী ব্য = ব ্য  ँ
Some words स्वागत  , स्पा, or अच्छा কী ক্লিক করে সময় বাঁচানো যায়
Instruction: this is simple Bengali client side code to type Bengali  text. I used button elements and Text-Area. Pleas avoid typing/editting with key baod.
This layer 2