Extensive reading can improve grammar and vocabulary
Reading and writing are interrelated. Reading improves writing and writing also improves reading, according to the California Writing Project, which aims to improve student writing and learning.
Benefits
Reading regularly can improve someone's grammar in a way that just listening to normal speech is unable to do. Books and other reading materials provide examples of new phrases, idioms and expressions that the reader can use when writing. Reading widely can also improve vocabulary, particularly if you look up the words you do not know and try to memorize them.
Expert Insight
Individuals with solid reading skills will tend to write well too, according to a study carried out in 2002 by Syying Lee and Stephen Krashen called "Predictors of Success in Writing in English as a Foreign Language." The study concluded that a person's reading level can help predict his writing skills.
Potential
Stephen Krashen, in his book "The Power of Reading," argued that free voluntary reading in school, where the pupil can make his own choice, is an effective tool to develop vocabulary and grammar and improve writing.
