Translation:Duo pays for the plane with camels.
I would be inclined to put für in this sentence, but I guess it's not needed. Would it be redundant and/or wrong to use? I can't remember if bezahlt usually uses für or if it's implied.
What exactly is going on with Kamelen here? I thought the plural was Kamele. I've seen some nouns change for genitive or accusative, but not for dative that I can recall. That's what this is though, right?
I cannot answer your first question (although, as far I know, ‘für’ would indeed be redundant, and if ‘für’ can be used at all, the form without ‘für’ is certainly much more common), but concerning the second one: dative plural nouns add ‘-n’ (e.g.: ‘die Freunde’ → ‘den Freunden’; ‘die Kinder’ → ‘den Kindern’; ‘die Männer’ → ‘den Männern’), except when the last letter is already an ‘n’ (e.g.: ‘die Frauen’ → ‘den Frauen’; ‘die Häfen’ → ‘den Häfen’) or when the plural is formed with the suffix ‘-s’ (e.g.: ‘die Babys’ → ‘den Babys’).
this sentence just takes the cake. First you have to take a huge leap of faith that you heard correctly: duo is using camels as barter. THEN you have to figure correctly that the plural "kamele" is not right because this is dative and thus, despite never learning the dative form of "kamel" and already recognizing you will never again in your entire life refer to camels as units of payment, you must use the correct form of the dative, "Kamelen." Not "kameln" as the voice says. Twenty minutes of my life I'll never have back again.
Well for me, as a speaker of American English, "for" really is necessary here. I can pay the check, pay the price, pay the charges, pay the bill or pay the piper; but I have to pay FOR the drinks, pay FOR the plane... (maybe because it is an elided form of "pay the BILL for the plane/drinks'???)
"Airplane" refers only to the flying vehicle (or toy) with fixed wings that provide lift. "Plane" may be used in place of airplane, but it also may refer to a woodworking tool that scrapes a surface to make it flat, or to the mathematical concept of a two dimensional surface with no curvature into a third or higher dimension.