We are pleased to let you know Windows 10 Mobile newly supports 10 Indic Phonetic keyboards below:-
1.Bangla (India) Phonetic
How to install Indic Phonetic keyboards:-
1.Go to Settings page.
2.Select 'Time & language'
3.Tap 'Keyboard' and 'Add keyboards'
4.Scroll to your expected keyboard and select it. (e.g. Hindi Phonetic keyboard.
5.Check Added Keyboard.
6.Download language data via Windows Update. It requires reboot.