It may not come as a surprise that the literal translation of the verb offrir is to offer. Whether there is an implicit purchase associated with the offer of a drink depends on the context of the situation in question, rather than with rules concerning French-to-English translation.
If you're at a bar, to offer somebody a drink would imply that you're buying it for them. If you're at home, to offer somebody a drink would imply that you're giving it to them. As you said, in this sentence the context is ambiguous so either of your translations work. However, "I offer you a drink" is the most literal translation.
I almost put "Je t'achète une boisson.", until I floated over the unnatural English phrase "I buy you a drink." and answered correctly. My question is would French speakers really say "Je t'achète une boisson." or "Je vous offre à boire (une boisson)./Je t'offre à boire (une boisson)."? Or would they say it like a question as we do in English (Can I buy/offer you a drink?) in the form of "Je peux vous offre à boire (une boisson)?", "Je peux t'achète une boisson?", "Puis-je vous offre à boire (une boisson)?" or "Puis-je t'achète une boisson?"? Would French people even offer to "buy" a drink as it is stated in the English translation or just "offer" you a drink? Offrir always means offer, in that case "Je vous offre à boire." would only mean 'I offer you a drink.' and not 'I buy you a drink.'.
It's not correct English. You can only offer nouns or noun-like phrases in English. You could say "I offer you something to drink" or "I offer you a drink".
Technically "I offer you drinking" is also a sentence, but it's strange and certainly not something you would say to offer someone a drink in a bar.
Count me in as one of many who don't understand why we are using boire in this sentence instead of boisson. Is it implied that we are offering to pay for someone to preform the act of drinking? (I know that sounds funny, but think of it in the sense of "I am offering to take you drinking"). So in this case we're referring to the verb instead of the noun?
Am I completely off base? That's about the only way I can make this work in my head.
This sounds more like an invitation than a literal act of offering to buy someone a drink. Since "boire" is the action of drinking and not the noun of an actual drink (boisson), this sounds like "I offer you to drink" or more correctly in English, "I extend the offer to go drinking", or "I am going drinking and I am extending the offer to you come along" - obviously not a valid translation of the sentence but more figurative in context.
Is it cheating to look in a dictionary? From Collins online:
- to offer sb a drink
Elle lui a offert à boire.
"She offered him a drink."
To me it seems like this would transpose to our sentence as
- "I offer you a drink."
This is accepted by Duolingo. Also, it's almost identical to the first post on this thread, from six years ago.