While the Burmese language is not currently listed in Keyman Developer, you can create a keyboard that references it anyway. Assuming you are using Keyman Developer 9, in the Code tab of the Layout page of your keyboard, add the following lines:
This will compile correctly, even though the Details tab in Keyman Developer will show
Unknown language x0455. Note that we don't yet have support for BCP-47 language tags (e.g.
my-MM). We are working on this, and when BCP-47 support is in place, it will replace the