If John’s son might be a writer, think of the benefits he would gain from any of those languages.
Tracy Simmons would put in a plug for Latin; so would my wife. I feel lame not knowing it, writing about 18th century Americans, so many of whom did. I feel less lame when I reflect that George Washington, didn’t; he had to read Seneca in translation, and yet he turned out OK.
I chose French, and I marched through the greatest hits from Francois Villon to Samuel Beckett. I read Cyrano de Bergerac in French (it’s a tremendous play, John Simon called it a fairy tale for adults, but it’s even better in the original). I read decadents and romantics (how Victor Hugo could crank out couplets); I read witty philosophes; I read grand tragedians. It was like living in a nice house, and having another, different nice house fourth-dimnensionally present. My French is sadly withered now. I can hack through simple prose with a dictionary, and did so when I wrote about Gouverneur Morris, who was fluent in it and watched the beginning of the French Revolution from Paris. But some bits are still lodged in the gray matter. Dieu, que le son du cor est triste au fond du bois.
But Spanish gives you Cervantes. I just read Don Quixote for the first time. Dr. Johnson said it was the only book we wish were longer. Harold Bloom says three people created the personality: Montaigne, Cervantes and Shakespeare. Montaigne created one personality, himself; Cervantes, amazingly, created two, Don Quixote and Sancho Panza. Shakespeare, incomprehensibly, created dozens.
But Italian gives you Dante, which is not too shabby either.