Reading is one of the best ways to continue to improve your understanding of vocabulary and grammar.
Vocabulary size, however, is strongly correlated with time spent reading.
There are three main things to keep in mind.
The first is that while increasing your reading matters, increasing your reading of fiction specifically matters equally as much.
Fiction reading increases vocabulary size more than just non-fiction — it makes sense, after all, considering that fiction tends to use a greater variety of words than non-fiction does.
The second thing is that, for people who already read “somewhat”, then for each level of “bumping up” their reading in general, or of fiction specifically, their vocabulary will be roughly 2,000 words larger.
Indeed, the difference between someone who reads “somewhat” and fiction “not much”, and someone who reads “lots” and fiction “lots”, is approximately 8,000 words, regardless of age level. That’s a huge difference.
And the third finding, completely unexpected, is that the difference between those who read “somewhat” and those who read “lots” doesn’t appear to change with age — the difference at 15 years old is essentially the same difference at 60, which means that this life-long difference is already present by age 15.
There is nothing objectively wrong with listening instead, however written content has everything easily accessible to be referenced, returned to, and looked up.
It’s also better in terms of sheer quantity of content available to learners, meaning there are more things that interest you available in the written form.
Reading and listening are simply diﬀerent ways of accessing the core components (vocabulary and grammar), which remain largely unchanged between the two content types.
If you only read you won’t improve your ability to distinguish sounds in speech, but you can work on that separately if necessary.
The key to extensive reading is that you read widely and a lot.
Finding a book
The most common way learners tend to get lots of language exposure is by ﬁnding a book they enjoy reading.
Graded readers, which are tailored to your level, are ideal. However, learners often ﬁnd books for teens or even pre-teens that they enjoy enough to read.
If the book is a translation of one you have already read in your native language, that will help you read a more diﬃcult book without losing track of what is happening. Harry Potter is one of the most re-read books by learners.