

English to Vietnamese or Vietnamese to English is harder than, say English to Spanish or Arabic because the sounds are so very different - I am sure I simply can’t hear some of the different sounds in tonal languages, and had a friend who moved here from Taiwan when she was so young she learned better in English than Taiwanese but still she could not hear the difference between ear and year.
I don’t think it’s impossible but do think it’s unusual. My dad was bilingual English and Spanish and I wish my parents had done the “one speaks English one speaks Spanish” language immersion but we only spoke English at home.
When I was a dancer - if one of us was injured, they made us come & watch the practice because apparently your body does gain knowledge just by watching.
But that was with a baseline knowledge already.
I think it would help, learning about swimming before doing it. More so if you are already physically active in some other way though.