What's in a name? In Alanna, names are like a portal into how this world works. They can tell us about who you are or what you can do. Even the absence of a name can be powerful, as with the Nameless Ones who are just so ancient and scary that the world has forgotten their names.
Check out how Jonathan and his friends don't call Ralon of Malven by his first name, though friends in the in-group do get called by their first names (Gary, Raoul, "Alan," and so on). When Jonathan explains that they're about to beat up Ralon for beating up Alanna, he says: "You were warned, Malven. You are no gentleman. You are a dog, and you shall be thrashed like one" (3.146). Talk about dehumanizing—Jonathan calls Ralon a dog, and also doesn't use his first name, but rather his family name! Using Ralon's family name is a distancing technique in that sense. It's like saying his individual identity doesn't matter to them. Harsh? Sure. But if you think about Ralon's personality, well, he kind of deserves it.
And then think about Alanna gives powerful, nature-related names to her sword and her horse, Lightning and Moonlight respectively. Lightning, true to its name, is a sword that you don't want to get struck with if you can avoid it. It's almost as though she's calling on these natural forces to help her, kind of like you'd name your kid "Grace" if you want her to be a ballet dancer and "King" if you want him to be, well, powerful. (Although, sad to say, we're pretty sure that one doesn't actually work.)
Speaking of kings, titles matter, too. George is called "Majesty" in the lower city even though, as a commoner and a thief, he can't technically lay claim to such a title. This disturbs Jonathan, as he's someone who has been born into royalty—legitimately. This parallelism almost makes us want to ask what the difference is between the King way up in the castle and the king of the thieves, anyway … but this is a Young Adult book, so we don't get too crazy with the social revolution. Plus, the two of them end up getting along, saving us from having to ask any really hard questions.
The fact that names come up again and again tells us that this is a world where names convey meanings and value. In some cases, it's a literal thing: the Nameless Ones are actually too terrible to name, and the fact that they're magical soul-suckers is related to this fact. In other cases, names reflect the social dynamics of the world—which is why it's insulting for Jonathan and his friends to not call Ralon by his given name. Neat, right?