If you're having problems like in the image below, it could be caused bycorrupt font cache files. What appears to be happening is that incorrector corrupted encoding vector information is being used when mapping thecharacter codes as input by your keyboard to the glyphs they representin the problematically cached font. You can use Font Finagler's Font Cache Cleaner feature to purge thesecache files in an attempt to restore normal behavior, and to help ruleout a font cache corruption as the sole cause of the problem. If,however, you use Font Cache Cleaner but the problem remains, then itcould be caused by a font conflict, by a corrupt orless-than-ideal-quality font, or by an underlying OS X font-handlingbug. Try removing fonts to isolate the problematic fonts that arecausing this behavior.