For example, at 10 years old, he wrote to his mother: "Today is your birthday, good Mother, and I am very happy to offer you my best wishes and blessings, and I will make this even nicer for you because I am writing in German."
At 16 years old, he wrote to his friend Carlo Bellingeri: "I am translating from Latin a bit of Quintilian, a little of the Tusculanae, and Horatio’s satire. It’s not wasted effort because they are all books which we’ll translate next year. Then from Italian (into Latin) some excerpts from the Decio Fantoni..."
Based on a letter to Carlo in 1918, it appears that he even studied Greek! "I'm still studying and in a few days I'll have finished the Latin textbooks, then I'll review my Greek about which I know nothing and then I hope to come to Turin to take those blessed exams."
In 1921, he wrote from Berlin to his grandmother Josephine Frassati, "I'm studying some German so that I can return to Italy knowing it well enough."While preparing for an exam in his major of mining engineering during February 1925, he wrote to his sister Luciana that he was awaiting "the arrival of a book in French and one in German to consult so that I can better prepare for the exam."