It will probably be because of the font, if the font does not support said characters, it simply cannot display them. Try using a font which support those characters and update me if it works or not.
Its not the font, my app have no problems displaying “äöå” if i type them direcly, its when its converting from the textfile to the array the “äåö” letters disapear,
I’d agree with the above reply but if that doesn’t work I’d also make sure your text file is in UTF-8 format too. (you can set this in Uniscite or programs like notepad2 under File->encoding)