Singing songs is correlated with the greatest reading achievement in the shortest amount of time with the most enjoyment of any intervention strategy available for struggling readers! 

Singing builds language retention, automaticity, vocabulary and fluency.

TUNEin to READING
In an accidental discovery it was found that students using a software program at home to improve their singing accuracy made surprisingly dramatic gains in reading achievement. After researching the effect, the company Electronic Learning Products developed TUNEin to READING to use singing as an intervention for struggling readers. 
News Video.  Teacher video.  Researcher video.  

After four years of studies of over 1000 students funded by the Florida Department of Education and JustRead! ($700,000), the average gain was 1.2 years of reading achievement in 9 weeks--singing three times a week for 30 minutes.  The gains were also reflected in the students' scores on the Florida state comprehensive tests compared with their peers who did not receive TiR practice. Schools and districts across the country are using TiR for struggling readers (Star Tribune). 

Dr. Tim Rasinski (informally known as the "guru of reading fluency in the nation")

A Teacher testimonial:
Today's workshop was given by Professor Tim Rasinski. If you teach reading, you probably recognize his name. He is noted for his work on fluency and he didn't disappoint. Tim began the workshop by asking us to join in singing three patriotic songs: Grand Old Flag, God Bless America, and Hail to the Chief. Timely, yes...linked to reading and fluency? Well, judging by the expression on some faces, that was questionable. Thus began a very unique workshop experience. Soon after the last notes faded away, Tim explained that singing is a sure-fire way to enhance both fluency and comprehension. He elaborated on the value of using songs to provide background knowledge related to our cultural literacy, have students discuss words found in song lyrics, and track text as they sing. Music was always a part of the day when I was a classroom teacher. I was delighted to recognize that I can continue to use music and it will actually benefit my struggling readers.