Plugin for user to type special characters

Hello!

Is there a plugin, that helps a user, not admin, to type special characters? That is, I could have a quizz with a gap excerise, where I expect the user to type “y?” in a text field. Since a big part of my users would come from countries, where they do not have “?” directly in the keyboard, I would like to provide below the text field a key to insert “?”. Something like:

Type in a suitable word:
…nnn [ ] nn…
[?][?][?]

where [ ] denotes a text field and [?][?][?] buttons, that produce the corresponding letter in the field.