Hogyan mondják angolul ezt a négy rövid mondatot?

„May I invite you for a coffee or a beer?” is Hunglish (and Denglish because Germans often make the same mistake). As a native speaker of English I can't think of circumstances in which I would use it. We usually say:

Let me buy you a coffee (or a beer) ... or, ... Can I buy you a coffee (or beer)?

In English we invite people to dinner or lunch (not „for”, by the way!) but it sounds a bit strange to invite people to have a cup of coffee.

If you're just trying to ask someone to join you for a cup of coffee you would use a phrase such as

Let's go for a coffee!

Shall we go for a coffee?

I'm sorry, if somebody said to me, "I'll buy you a coffee", I'd say, "no thanks, I'll buy my own". To invite someone for a coffee is not Hunglish, not even Denglish. I hear this phase every day, in a native speaking setting. It is a very polite way to ask someone out, nothing odd about it.

Thank you for putting your two cents in though.

There’s always something new to learn! Thank you for the salutary lesson in English, Poindexter.

Anyway, no offence meant! Are you up for a coffee sometime?

WeCanDo, Piondexter I am not, but coffee any time! Down Under?

No, seriously, your suggestions as pick up lines, are too casual for me.

Then again, depends on who and where you want to pick up.

No, of course, not offended at all!

If I ever come to Down Under I promise I'll drop you a line and we can meet up, grab a cuppa and a chat.

Anyway, I guess we're drifting towards off topic ih this thread and we might do better to conclude our private discourse.