From my german point of view I never thought of something being wrong with ABBA's english. Should I have noticed that what was wrong was the fact that I could understand it? Should I have understood that one of the reasons for their success in Europe might have been that their lyrics (although in english, which is not the original language of most Europeans) could be understood by many people in Europe? (Of course english is also fashionable, please don't make me tell you details...)
I have always been enchanted by the possibility to communicate with scandinavian girls (yes! - why only girls?) in english. Not too long ago somebody told me an explanation for that: They watch all the movies with what is called "sub-titles" in german (is that the correct expression for those lines of text at the bottom of the screen?). In Germany all the movies are "synchronized" (i.e. a the sound is replaced completely by a german speaker - no english left, but the whole thing has developed to some kind of art...) So no wonder if the scandinavians are better in speaking english than the germans are: They just listen to it while being able to read what it means.
It is much more difficult to talk to somebody whose original language is english. Not only because of their special accents: Those people simply don't know what is taught to be english in foreign countries.
And now I read Peter's and McGrath's annotations...
I'm sure that english is going to be the future "lingua franca". That's good. Any other language I know would be much too hard to learn for a foreigner. (There's beauty in those special kinks of some languages, but in the end having to cope with them is only kinky and by no way beautiful.) But - my english speaking friends - this donation you give to the world might also suck some blood out of your gift. Maybe you can refer to the lyrics of ABBA to anticipate some impression of how english will be spoken in the future (ouch or not ouch that's the question).
BTW - I am also interested in a way to do some of ABBA's songs on the guitar. I'm still convinced that if I only tried I could work out some quite nice versions. I started to believe that about twenty years ago, but if you asked me for just one of those quite nice versions today... err...