this must be a Dutchman asking...
So, for vs til? I'm a bit confused on that. Is there some kind of consistency?
Betale for = pay for. They are paying for your meal or something, you don't have to use any money.
Betale til = pay to. As in they owe you money or want you to finish the bill for them, they give you those money.
Is the safest way is to say "betale for" which will include cache, cards and bitcoins? "betale til" is only for cache?
It merely concerns the transition of the value, regardless of the format (card, cash, bitcoin).
Could not this de be translated as polite you ... As in Pouvez vous payer svp?
No. The polite "you" is both very dated in Norwegian, and spelled with a capital "D".
The only time you'll see it used in contemporary writing, is in letters from international companies unaware of how stilted and old-fashioned it sounds.
Is it simply not used anymore, either in speaking or writing? In other words, has 'du' become universal and acceptable in any situation, even if you don't know the person and would like to make a good impression?
Yes, you can consider "De" completely phased out.
Interestingly, Kirsti Mac Donald teaches this form, with no mention of its being dated, in Norsk Grammatikk, published in 2009.
Why is it "betale" and not " betaler" ?
Modal auxiliary verbs, such as "kan", "må", and "vil", are followed by a bare infinitive, i.e. an infinitive without the infinitive marker "å" ("to").
infinitive: å betale = to pay
present: betaler = pay, pays, am paying, is paying, are paying
If you press the microphone button and then click on the button to play the phrase, it'll do the speaking for you....
I've done that by mistake...