"He swims every Wednesday and Saturday."

Translation: Er schwimmt jeden Mittwoch und Samstag.

[lexx_it]

Why "Er schwimmt jeden Mittwoch un Sonnabend" is not accepted?

[az_p]

Duolingo has previously made the decision to stick with only the High German translation Samstag for "Saturday". You'll find that's generally the ruling on dialects (even major ones).

[quis_lib_duo]

Except, the use Sonnabend is not a dialect. It's a variant more prevalent in Northern Germany, true, but it is High Standard German (unlike Sünnobend, Saterdag, Sünnavend).

"Sonnabend ist der zweite hochsprachliche Begriff für den Samstag, er steht im Nordosten..."
( http://www.zeit.de/2012/30/Deutschlandkarte-Samstag )

[Max.Em]

Sonnabend was used by my grandparents, in the middle of Germany, but in my generation or the one of my parents I did not hear it anymore.

[quis_lib_duo]

Headline from today: http://www.haz.de/Hannover/Aus-der-Stadt/Uebersicht/Das-ist-am-Sonnabend-in-Hannover-los7

In detail: http://www.haz.de/Hannover/Aus-der-Stadt/Uebersicht/Hannover-Sonnabend-drohen-Verkehrseinschraenkungen-in-de-Innenstadt

From Hanover, the epitome of Standard High German.

[mizinamo]

It has?

I don't see that choice in the internal Translation Guidelines, and when I had a look at that unit, all the other (older) example sentences for Samstag all accepted Sonnabend in the reverse translation.

As far as I can tell, this was simply an oversight -- this sentence is newer and the contributor who added it didn't think to add the alternative Sonnabend in the reverse translations.