Thank you for the concepts of "2nd language environment" ,as I summary might be

1. It need sufficient exposure of  "understandable sound"
..This make me think what an english pronounciation trainer here said 
" Native usually understand poor grammar though they feel skeptical  but
hardly tolerate poor pitch" .. From my feeling, an effective way to learn this may be chatting to native speakers 'friend' ( who I percept they like to talk with me).
  It also very interesting to know how often and how many hours per week would be optimal for adult learner.

2.The input should be "Scene and Sound"  coming together like real life conversation, video.
..My experience supported this concept. First time I prepared listening skill for an english exam I solely listened audio file -> it did not work. Afterthat I changed to view news clip and noticed somewhat more effective.

These are really useful for me to figure out how to create such environment in our workplace that the 2nd language is "Kummunang"(คำเมือง) :-D.