Audibooks are particularly beneficial for those strong readers, who may have a huge vocabulary, but may never use those words in speech because they seldom hear them pronounced out loud. (For example, I was very embarrassed the first time I pronounced inventory out loud in school as a child.)
But audiobooks are beneficial for all readers. Often, we want to read, but feel tired or have many other demands. Students can listen to an audibook in place of music on their cell phones (outside of class).
Audiobooks can help students push slightly above their reading level to experience a book their friends are talking about, and can help students begin to learn their preferred genres, authors, and series.
Audibooks can be expensive. The Libby phone app lets you rent audiobooks from your library straight to your phone.
A lot of recent research has found that for most students, reading on paper is slightly more beneficial than reading on a screen.
That being said, students who struggle with organization may benefit from an e-reader that saves their page for them. Additionally, amazon kindle and other e-readers, even just the app on your phone, can define words for you when you hover over it.
Kindle also offers the option to create vocabulary lessons based on words that appear in the books you have read.
(Usually done through Amazon Whispersync)
Using something like Amazon's audible alongside the Kindle app on a phone or a Kindle itself, students can have their ebook and their audiobook sync. This way, they can listen to their book during the day, and still read for 30 minutes at night, picking up where they left off.
In my opinion, this is the best possible way to help a lower reader. By starting a book on audiobooks, they hear a professional give voice to each character and can begin to get hooked. Then they gain reading stamina by practicing on their own.
All three of these illustrated reading options have books and series available up to an adult maturity level with an advanced vocabulary.
If this is your child's area of interest, consider doing some research to ensure you are okay with the content and themes, and then push them to read outside of their comfort zone in these areas.
As an alternative, provide a huge QUANTITY of these books and encourage your child to race through them, as they are often intended to be long, addictive series. This will expose them to significantly more vocabulary and concepts than if they stick with just one series.