My aim in this thesis is to investigate how an American teenager’s idiomatic language is used by the protagonist in J. D.Salinger’s The Catcher in the Rye (1951). The objective is to develop the communicative competence of Hungarian learners of English by extending their vocabulary using excerpts from the novel. The enlargement of the lexicon will happen through reading in order to identify the new words, while writing and speaking activities will help students to incorporate them in their oral communication. The acquisition of new vocabulary items will basically aim at the informal register, the students will be familiarized with the usage of American slang and idiomatic language use in the 1950s, yet still in use today. The intended level of students is upper-intermediate, 17-year-old Hungarian learners.