The Annotated Lolita is the only version of Lolita that should be read by students and Nabokophiles. If you don't speak French, much of Humbert Humbert's comments will be meaningless; the annotated text does a good job of translating, not only words, but any literary allusions or puns that Nabokov makes in French.
French phrases aside, The Annotated Lolita also offers insights into Nabokov's intentions within the novel. Many of these would be lost on the reader if not for the annotator's notes, or simply missed on a first read. Comments from Nabokov's own lips also appear within the notes, taken from interviews and direct conversation with the author. This offers a glimpse into Nabokov's writing and thought processes beyond what appear in Lolita. The annotator does not neglect Nabokov's other literary works or interests and describes how the author's experiences affect the actions and opinions of the characters.