AbiWord does not "write" the signs I type

When typing a text - or even when copying and pasting a text from another application - the signs are transformed into other signs (from a different language?) - making the text unreadable. How can I get rid of this problem?

edit: This problem seems to be linked to the "Times New Roman"- and "Arial"-font. However, the font works flawlessly with Microsoft Word. Any advice?