1. Well first of all, like I said in the lecture itself, passage 1 isn't just about a "phenomenon".
Right now, it's not important whether the phenomenon refers to just language acquisition or languague acquisition making people fail to see the world as a whole because passage 1 is just an "opinion".
What the author of passage 1 is trying to say is just his/her view.
2. Well if you look at the passage a little bit more carefully, it's not just one sentence.
It's more like 80% of the first paragraph which focuses on the benefit of language acquisition.
When we are born into this world, all sounds are incomprehensible, but through language acquisition, we come to associate objects with certain words.
What is stated in pararaph 1 is just concisely restated in the beginning of paragraph 2, and paragraph 2 then focuses on the author's viewpoint.