I know I am late for your answer but I am still going to answer so that whenever someone faces the same question again, they don't have to go to a lot of places to find their answer.
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When choosing another language with booster, what texts are being translated?
a) the Shopify program?
b) all menus, text on buttons, naming of categories, ...?
c) all text added as subscription of products and pages?
and, is the language picked automatically when visitor is in a different country/location?