Note: on the version of this question that has you pick the cards, こんばん and は are separate. This makes the は sound like "ha". Its important to know that when は is at the end of a sentence, it is pronounced "wa". When it is part of a sentence or word it is pronounced "ha".
I was stationed in Okinawa for 2 years. I picked up some of these weird tid bits.
は is not pronounced “wa” at the end of a sentence. It is pronounced “wa” next to a subject noun.
(Since Duolingo app is stupid and can’t edit the comment, I’ll just reply to this).
Next to a subject pronoun so it works as a “subject particle”.
*arigatou as in ありがとう. The difference is that the "o" is held longer. This may sound silly but it can GREATLY affect meaning. 家(いえ) would be house while いいえ is no. My favorite example is that the slang way to say yes (yep/yeah) is うん while the slang way to say no (nope/ nah) is ううん.
What nakada tries to explain is that the construction "konban wa" comes from an old way of greeting were the first person said this beggining of the sentence ("this evening...") like waiting for the other to continue it, as to begin a conversation. So he's right, of course: the "wa" particle is here marking the subject of a sentence that is left uncomplete.
Yes, the "wa" here is actually the topic particle は
こん - now/this ばん - evening は - topic 'on the topic of this evening....'
replacing it with the kana for "wa" わ which isn't a particle is kind of like using "U" instead of "You". They sound the same but it's not really proper
What does こん mean? I have seen it in こんしゅう, translated to this (this week), being こん represented with 今。 Does こんにちは mean (in a word by word translation) this (or today's) evening? I think Japanese often give you some words and you just understand because you dont ask yourself what does good morning mean.
If we are being technical, you are both wrong.
A direct translation of こんばんは is something like "As for this evening ..." or "Regarding this evening ..."
But since it is used as a set phrase evening greeting it gets naturalized to "good evening" or "good night" in English.