Windows 10 Mobile : How to add japanese keyboard

can't add japanese keyboard ?

1. Settings -> Time & Language -> Keyboard

   • Japanese 12 Key
   • Japanese QWERTY

2. When check on to install :
   Attention Required, retry to download the Text Suggestions, Preparing Download never success

How to install japanese keyboard ?

1. Setting -> Time & Language -> Speech
2. Download a speech language -> Add a language
   • Japanese
3. after download reboot
4. Settings -> Time & Language -> Keyboard
   • Japanese 12 Key
   • Japanese QWERTY

Note:

• Once Speech language Installed, cannot be removed except full-reset of Windows 10 Mobile ....