Translation:What does he say
I'm by no means an expert, so don't take my word for it, but maybe it's just supposed to be stressed more than regular monosyllabic words. For instance, in Spanish, él (he) is stressed slightly harder than el (the) even though it's monosyllabic. Perhaps we'll come across a word in the future that's just spelled "τι", which has a different meaning.
I think from my days learning Ancient Greek I remember a distinction between τί (accented) being a question word ("what?") and τι (unaccented) being a pronoun - big disclaimer: I may be mixing this up with Spanish (which I learnt afterwards) and/or misremembering. It's been a while since school...