Minecraft chat not readable?

I play Minecraft pocket edition on my cell phone and iPad and I haven't been able to read the chat for a week (when other players write something in the chat). I've had this before but that's a long time ago it was because of an update and I hadn't updated it yet but there's currently no update. Does anyone know what I can do about it because my chat is switched on if anyone says that I might have issued it.

Can't you just read or write no messages?

I can't read it