Language, Culture, Human Brain, and Consciousness
Human being are social creatures. A large part of brain/mind is for social functions. In a foreign land, because of the language barrier, those functions are rarely carried out, thus those parts of brain rarely exercised, and might go into hibernation for a long time.
Even foreigners/immigrants choose to stay within their ethnic communities oversea, these communities don’t form a large society at all, thus lack many social functions the brain needs to develop itself socially.
As a foreigner, s/he cannot feel any more those things s/he used to feel strongly. S/he cannot continue the social learning/development of the brain/consciousness, thus cut off from the life path s/he has been on (whether s/he is consciously aware of it or not).
Unless the foreigner can fully embrace the new culture and overcome the language barrier, thus get in touch with those collective social functions (attributes of the social space), the foreigner cannot overcome herself/himself and continue her/his growth or worse, s/he gradually dies socially.
Yes, the brain needs to be used socially, thus many aspects of it can develop as a space. These strong feelings, after all, are experience of brain of the social space. For example, the experience of no thinking and just experiencing.
With the mother culture, the brain develops in an organic way as the person grows. After the language development stage, the brain starts to develop socially. Compared to the brain development during the language acquiring stage, which happens naturally and most people or all people are able to accomplish without a problem, this stage of brain social development takes extraordinary individual efforts, and most people are not able to develop this stage consciously and completely. The compulsory schooling and various other crowd control techniques are adopted by the ruling class to intentionally restrain its development and thus for many many people, this stage of brain development is not very much started and thus they stay as very dependent and immature people.