According to dialogue box he supposed to say "The son of Mundzuk greets you." or as we all expect sth like "I am Atilla" but i hear neither Mundzuk nor Atilla. Did anyone heard he said any of those?
The text in the dialog box is independent of what they're actually saying. See for example Washington and Elizabeth I. And notice that they always say the same thing when you meet them, but the text will be different. It's not meant to be a 1:1 match.