I've connected to my phone a desktop USB keyboard using an OTG connector. Everything works fine, unfortunately I can't produce accented letters like áéíãê.
When I type an accent, like `'^, another symbol prints. I expected the behavior of a dead key, followed with the accented letter.
The keyboard has a Brazilian ABNT layout. I tested it with Google Gboard and Samsung standard keyboard. Tested with languages English international and Brazilian Portuguese.