This has been an issue since 11.0, or so.
When I place a sign and I start typing, it either closes the game without saving or it shuts down my entire device (kindle fire).
If one happens to work I can only read it when it's on a two blocks space (at eye level) and I have to shift a certain way to see parts of it.
Why is this happening to me and how can I fix it?
Best Answer
You may be able to use Block Launcher as a workaround. It's an Android App that allows you to enter text, which is inserted to the game.
According to this answer, the text mode is used as a workaround for devices that don't allow you to enter text at all into Minecraft Pocket Edition - it should also work for your purposes.