In Lolita, words are Humbert's greatest weapon and favorite toy. He is verbally adept and constantly assessing others based upon their ability to use language. Because he talks about words so much and happens to be our narrator, we have to watch out for him. Since he has been instructed to tell his story by his lawyer, we can be sure that he will take every opportunity to cast a favorable light on his behavior.
While Humbert certainly fesses up to unforgivable bad behavior, he still offers highly poetic descriptions that serve to distract the reader from the subject at hand. If it weren't for his skill with language, we would be faced with a stark account of Humbert's crime; instead, he makes the story an appealing one in spite of the grisly subject matter. In other words, he makes a story of rape, pedophilia, incest, murder, and exploitation beautiful and "enchants" the reader into sympathizing with him. He is particularly drawn to language of magic and fascination, fairy-tale like images, and references to "magic potion" (1.27.138), "crystal sleep" (1.28.1), and other dreamy images. He also makes appeals through legal language, sneaking in justifications and defenses of his behavior. To understand the full extent of his love of words and his manipulation of the reader, keep your Oxford English Dictionary at arm's reach!
Language is Humbert's best friend (all he has to "play with") and his worst enemy, because he cannot help but detail his obsession with Lolita.
Love of words ties Humbert to Quilty more closely than Humbert would like to admit.