Recommend books to English leaner

Pick something fictional that you might read in your own language. If you like mysteries, that would be a good choice as they use lots of conversational language. Same for romance novels.

I suggest you avoid material with language specific to a specific field. If you are learning a language, save the philosophical topics till you've got the everyday usage under control.

Reading plays would also help. Plays are almost entirely dialog, and are usually rendered in casual, ordinary language. I'm not talking about Shakespeare, but more contemporary authors. Neil Simon might be a good idea. He writes comedies, and they're about ordinary people.

Thornton Wilder and Wendy Wasserstein also come to mind - good dialogue and the usages are contemporary or close to it.

Thanks a lot!