@lightingcloud What you guessed is sort of... half-right and half-wrong.
The text is written in katakana, not in the Italian orthography:
Read literally, this says "initsia - ra - paruti-ta!!"
After feeling it out for a bit, it was pretty clear it wasn't Japanese or English, especially given Tanaka's comment immediately after. Googling some alternate spellings got me to what you see in the chapter.
As for why Italian, though? No clue. I've come to accept as I work on Ueno-san that, more often than not, I'm not supposed to ask "why" and simply roll with it.