I recorded myself rehearsing for my talk at #IATEFL2024 in Brighton but realized afterwards that I had skipped a slide that I needed to include as it was about how ER improves even speaking. this is what it said:

Why do Extensive Reading? "When EFL students read extensively, they become fluent readers. But there is more. Studies have established that EFL students increase their vocabulary and become better writers. We also know that reading extensively helps increase oral fluency—listening and speaking abilities. Finally, students who read a lot develop positive attitudes toward reading and increased motivation to study English. So, there are some excellent reasons for having EFL students reading extensively."

(Dr Richard R. Day in Bringing extensive reading into the classroom, OUP 2012)

You can watch the 25-minute video here: 
Extensive Reading improves every skill, even speaking. Try it! IATEFL Brighton 2024