[lqet]

> However, Stephen Krashen's Input Hypothesis expounds that language acquisition occurs only during exposure to new language and not while speaking.

I think exposure and actively speaking are the wrong categories - your learn a language by using it to participate in a common experience with another human being. For this, you both have to use the same protocol, and at the beginning, you have to figure out this protocol using a simpler fallback feedback protocol. This is something I am currently realizing as a father of a one-year old. This involves of course exposure and speaking, but I strongly doubt that you could learn a language just by listening to it and re-producing the words. I expect this would only result in text/speech resembling GPT-2.

I also think that you can have a common experience without actively producing text or speech, for example by watching a movie / TV show were you want to follow the story and participate in the lives of the actors. In fact, I know many people who effortlessly learned a second language by watching foreign movies and TV shows for years.