Constant unintentional typos? (kana)

You may want to check out this script. I don’t use it personally but it seems to be what you are asking for.

If you think you have strong self-discipline I’d recommend installing this one instead:

If you make a genuine typo you can reset it and enter your answer again. However, this script does mean you can mark incorrect answers as correct so only use it if you know you’re not going to cheat yourself!