This is more or less the central debate of the movie (if there even is one), which tracks Tolkien's adolescence and young man-hood before tossing him and his "fellowship" of schoolboy friends into the mire of World War I. What about language gives words their importance? Is it the way they sound, as he thinks, or what they mean, as Edith says? Tolkien would, of course, go on to use his aesthetic theory in his stories anyway, often as a signifier of either good or evil. The language of the Elves in Middle Earth is beautiful; the language of the creatures of Mordor is ugly.
If you know anything about The Lord of the Rings and Tolkien himself, you probably know that, yes, it was his friendships as a young man that inspired the characters and camaraderie of The Fellowship of the Ring, and it was fighting through the worst war in history (at that point in time, at least) that drew him to creating tales of good warring against evil, dark, powerful magic, and terrifying creatures.
That's certainly interesting and inspiring, but it's not enough to provide a clear, exciting backbone for a movie, which is why a lot of Tolkien feels like a very by-the-numbers biopic. Both Hoult and Collins are great in it, because they're both wonderful actors, as are many of the cast. The OA's Patrick Gibson, who plays Robert Gilson, is a welcome, hilarious presence in Tolkien's crew of young boys, and Shakespearean veteran Derek Jacobi appears late in the film as one of Tolkien's college professors. Even Colm Meaney is in it as Father Francis, a priest who took orphaned Tolkien and his little brother under his wing after their mother died, and who convinces Tolkien to go to college instead of marrying Edith.