Learning a language requires that you master some combination of the four main linguistic skills: reading, writing, speaking and listening. With this in mind, it's possible to learn reading and writing in English through written literature, as it provides not only a basis for the written language, but also a real-world context. Although this method is not without its pitfalls--for one, you need to make sure the books you read are set in a time period that is linguistically congruent with your own--it can help you successfully master the English language when used in tandem with other techniques.
Learning English Through Literature
Research the author and the book to ensure the language being used isn't specific to a time period far in the past. For example, although some of the turns of phrase in John Steinbeck's "The Grapes of Wrath" might help you when crafting your own short stories or novels in the future, you will find that books set within the the past 20 years or so will contain more useful language.
Use phrases you see in literature when writing your own letters, emails and stories, but don't stop there. Spoken language is arguably just as important as written language, so it's important that you use your budding mastery of reading and writing in conversation with friends. Incorporate words and phrases into your conversations organically rather than quoting directly from the literature to avoid seeming awkward or unnatural.
Read a wide variety of literature to develop your range of vocabulary, phrasing and subject matter. Select as many nonfiction books as you do fiction and read a female author (or, in the case of fiction, a book with a female protagonist or main character) for every male author you read. Study the language used by authors and characters of various economic, ethnic and social backgrounds to gain a wide perspective of linguistic differences across various spectra.
Keep the purpose--and whom you perceive to be the intended audience--of the work in mind when you re-use the language with others. For example, you can feel safer using language you read in a book by a respected author such as Jonathan Franken or Chuck Palahniuk than reading one by a reality TV personality such as Snooki or Lauren Conrad.