Dictation works great in English. I switched to German and words without Umlaute (ä, ö, ü) are recognized well. If there's a word with an Umlaut, the Umlaut is interpreted as some other instruction and screws up the existing text, splitting words and moving the cursor.
Is this known, or do I have to change a particular setting? I used both keyboard layouts, English (International) and German. Same behavior.