How do you say "immersion" as in "full immersion language program" or "I am moving to China so I can get some immersion in the language"?
Although in a 洗禮(baptism), a person may be immersed in water for a brief moment, but the purpose of baptism is mostly for symbolizing purification or regeneration. For example: 經過戰火的洗禮 (After the baptism of war). It is not a very good translation for "immersion" in this case.
沉浸 is the correct translation for "immersion"
"Full immersion language program" in Chinese should be 全浸式語言課程
Another suggestion :
單語環境學習課程 (single language environment study course)
I have only seen the direct translation of 'full immersion language program' once in an advertisement of a very specific English summer program, it is not a common word that you would go out and say to native speakers telling them that you want 語言洗禮 or 浸禮, because a lot of the time it would be interpreted as baptism. Tang Ho's answer '全浸式語言課程' is as close as it gets for a direct translation.
However I would suggest to use 'experience' 體驗 or 'train' 訓練 as an alternative for 'immerse'.
I would like to fully experience the Chinese culture and practice my language, therefore I am moving to China.