I can't use the character (accented) selector on my Android phone. It disappears when I try to type
Im not part of the tech team, but I do have an Android. Is this the first time you´ve tried to use it? Or has it been working previously? If it has been working previously and just stopped working, I would contact your cellphone carrier because it might be a problem with your phone, rather than Duolingo.
If this is the first time you've tried to use the accented selector, hold the button down on your phone, then slide your finger to the accented character. Don't lift your finger or it will disappear.
I hope this has helped!