Is he on the brink of an explosion of words?

my 17 month old had been very active but also very quiet, he didn't say much so I placed him in speech. They still haven't decided if he's shy, doesn't care about talking, or have problem saying more words because he just won't say anything to them. Anyway, recently he has gotten more active, and has increased his baby talk like crazy, the other night he talked himself to sleep. He asks me questions and protest in baby talk every day all day now. So based on your experience do babies have an explosion of gibberish before an explosion of words