I recently changed my mind about opting for Italian musical terms in my scores.
It came after receiving a new score with Italian marking such as Più Mosso and Meno Mosso, among others. It came because they were in a score written by a Swedish composer.
The argument I’ve heard made before is to use English markings in my scores, because they are less pretentious and more immediately receptive to the readers of my music. I certainly could default to English – it will make my own students happy, because they aren’t fluent in Italian musical terms! But it’s also provincially minded to use English terms as an English speaker. My friend didn’t use Swedish terms, though I’m certain they exist, because he understood that they wouldn’t mean anything to me. He chose Italian because they are the closest we have to universal musical terms.
I don’t pretend that I think my own music will have a worldwide reach. But I do think that it shows a respect for musicians beyond my borders if I make my notational choices as universal as I can.