One example of the results of language acquisition
Here is a discussion in Japanese between a polyglot Canadian (Steve Kaufman) and an American citizen (Matt). Both individuals are self-studied in Japanese using immersion-based approaches based or influenced by Stephen Krashen input hypothesis. The topic of the video is suppose be something like: For what reason/what purpose are the study of English, Japanese? If you do not happen to understand Japanese you can use Youtube's automatic subtitles/close captions to automatically tranlate the audio into English or whatever other language youtube offers.