An argument can be made, too, that both Afrikaans and Swahili approach the simplicity of a creole; they're certainly closer to being truly rule-based grammars than most of their relatives (which tend to have accreted a lot more arbitrary classifications, exceptions and etic peculiarities). Standard Arabic is also relatively simple, being more of a regional lingua franca than a typical everyday language (much like Europeans slipping into Latin for political or scientific discourse).