Took me a while, but here's the solution:
Step by step:
(Note: I like full square grids for solving these riddles, helps me spot any squares I missed marking off. The information is the same as in a triangular one, just doubled along the main diagonal. I marked new entries in a different shade of red and green compared to the old ones, so it's easier to see what is new compared to the last step.)
First, this is the base grid: Only interesting thing here is that the first and second language obviously have to be different.
Next, include everything that is directly stated in the text. Clue 3 blocks everything Polish from another and from Connor.
Clue 4 tells us a few things:
- Kellan doesn't speak Polish as his first language
- The man destined for Czechia isn't the man who grabbed the Czech ticket
- The man who grabbed the Czech ticked speaks Dutch as his second language
- Neither of {Kellan; the man who speaks Polish as his first language; the man destined for Czechia; the man with the Czech ticket} speaks Irish at all
- As Bernard couldn't communicate with the man with the Czech ticket (who we know speaks Dutch), Bernard doesn't speak Dutch
- As Connor is neither a native Polish speaker (per clue 3) nor is he called Kellan, Connor is none of the people in clue 4, meaning he doesn't speak Dutch as a second language, didn't grab the Czech ticket, and didn't want to go to Czechia
Clue 5 doesn't give use any information that we can directly fill in, so will will get back to it later. Clue 6 tells us that Lars doesn't speak Zulu, as every language is only spoken by two people, and Lars is swapping tickets with both of them.
Before we come to clue 7, we should think about the whole swapping process. Swapping tickets only makes sense if one of the participants is aware that the other man has his ticket. We know that the man from clue 8 already has the correct ticket, so he won't swap with anyone. James also never swapped his ticket per clue 8. But since he didn't start with the correct ticket, this must mean that he was unaware that he had the wrong ticket and couldn't understand what was written on the gate he ended up (and he importantly didn't expect to, because otherwise, he would be suspicious that he couldn't read anything at his wrong gate, and search for his correct ticket). Otherwise, if you recieve a new ticket, you go to that gate. There were three swaps, and four people that moved around (everyone except the lucky guy from clue 8 and James).
We also know that only the guy who started at gate 6 noticed that his ticket was wrong (per clue 5). We also know that he went and found his Dutch flight, where he then swapped tickets with the man there. This man then checked out gate 6. He also realized that this isn't his flight (otherwise, there would be no more reason to keep swapping tickets), and went to the man on the desk (only the first guy actually checked the gates directly to look for his flight per clue 5!). The clerk told him the correct gate, where he swapped his ticket with the man there. This third man also checked out gate 6, realized it wasn't his, went to the clerk, found his correct gate and swapped his ticket there. This was the third swap. The last guy went to gate 6 as well, didn't find anything wrong with it and stayed there, breaking the chain of swaps.
Back to clue 7: We know that the last swap involved a man with a Spanish Ticket per clue 6. We also know that the one swap involved a man who wanted to go to Spain. These must refer to the same swap. Otherwise, the man travelling to Spain would already have his ticket from one of the previous swaps, and it wouldn't be passed around at the last swap. Remember, you don't swap tickets unless at least one person gets their correct one. Together with clue 6, this means:
- The man travelling to Spain knows Dutch (but we don't know whether as a first or second language)
- The man with the Spanish ticket has Czech as his first language
- The man travelling to Spain doesn't know any Czech
For the lucky man from clue 8, there are three options left for flights where the grabbed ticket was the correct one - Ireland, South Africa and the Netherlands. These are the same countries as in clue 2. As the lucky man was at the correct gate, he didn't miss his flight, and was therefore travelling home. This means that his second language is Spanish (as clue 8 says that he speaks Spanish) and his native language is the same as his flight and ticket. However:
- The man from clue 5 was looking for the Dutch flight. Therefore, the lucky man can't be on that flight as well.
- Both Zulu-speakers were involved in ticket swaps per clue 6. As only two men speak each language, the lucky man can't be from South Africa.
The lucky man is therefore from Ireland, travelling to Ireland with his correct Irish ticket, and he speaks Spanish as a second language.
We know that Mr. Lucky-Irish isn't called Lars (had to swap his ticket with the Zulu-Boys), James (missed his flight by standing around), Bernard (speaks Czech) or Kellan (Mr. Lucky-Irish neither went to Czechia, nor had he the ticket for it). We also know that since he speaks Irish and Spanish as first and second language, the reverse option is blocked for everyone, as no two men speak the same pair of languages.
We know that the guy who started at gate 6 (call him Gate-6-Guy) successfully found his Dutch gate. As he found it, he hasn't missed his flight. By clue 2, we can conclude that the guy flying to the Netherlands flew home, so Gate-6-Guy has Dutch as his first language. We also know from clues 6 and 7 that the other guy speaking Dutch wanted to go to Spain, so those are the two travel destinations of Dutch speakers. We also know that the guy who wanted to fly to South Africa missed his flight.
There need to be two people who missed their flights: James, and someone else who has James' ticket. The only person who could end up with the wrong ticket is the one who swapped theirs in the third swap, checked out gate 6 and found nothing wrong with it. This poor sod (I call him PoorSod) would be the Czech man who initially grabbed the Spanish Ticket. Regarding James: As he was stationary and didn't swap his ticket, he is
Not Gate-6-Guy
Not a zulu speaker
Not the Czech man who grabbed the Spanish ticket (who after all swapping has James' ticket)
Now we think about the gates, and figure out where the first swap between gate-6-guy and the other man he gave his ticket happened. We know that he started at gate 6 and went past at least one other gate until he found his flight, so that rules out gate 5 as well. Gate 3 is occupied by Mr. Lucky-Irish, and gate 2 is where the final swap happened, so it can't be the gate he was at as well. This leaves gate 1 and 4 as the only two options.
We also know that there were four instances of people running across gate 3 per clue 8. If gate-6-guy found his Dutch flight at gate 1, he would cross gate 3 once on his way there. The man he swapped his ticket with would then run to gate 6, find out he's wrong there and head all the way back to the clerk next to gate 1, resulting in two more runs across gate 3. He then goes to his correct gate for the second swap, and the only options for that are gates 4 or 5, bumping us up to four runs. But the next guy also goes to gate 6, heads back to the clerk, swaps his ticket at gate 2, with the person there also heading to gate 6, which adds up to two more runs. So gate 1 is out, and the Dutch flight is at gate 4.
Now, languages: We know that there are six languages, and we know per clue 3 that there are two polish speakers, and one person who can communicate with both of them. This is only possible if three people form a sort of language-triangle where they share three languages between them. X and Y speak Polish, X and Z speak common language A, Y and Z speak common language B. As this leaves three men out, they also must form such a language triangle.
We know that Lars is in the same language triangle as the Zulu-Speakers, as they could swap without language problems.
As PoorSod (the guy who missed his flight despite swapping at the 3rd swap) speaks Czech and couldn't communicate with Lars or the Zulu-Boys, he's not in their language triangle
Gate-6-Guy speaks Dutch, and was involved in the first swap. Therefore, Dutch is in the same triangle as Zulu.
As Mr. Lucky-Irish speaks both Irish and Spanish, these two must be in the same triangle. This must be different from the Zulu-Dutch-triangle, as there can't be four languages in the same one. Therefore, Irish, Spanish and Czech must form one triangle, and Dutch, Zulu and Polish the other one.
As Mr. Lucky-Irish speaks Irish as his first and Spanish as his second language, the other two pairings in that triangle are forced as well: One man speaks Spanish as his first and Czech as his second language, the other one Czech as his first and Irish as his second.
The plane at gate 6 was correctly identified as not their plane by all three men of the Zulu-Dutch-Polish-triangle, while PoorSod from the Czech-Irish-Spanish-triangle didn't understand the signs there. This plane can't be from Czechia, as PoorSod would've noticed that this is not his plane. It can't be from Ireland, as that plane is at gate 3, and it can't be from Spain, as that one is at gate 2, where the final swap happened. It can't be Dutch, that one is at gate 4, and it can't be from Poland, as the man who grabbed the Polish ticket can't be in the Polish language triangle per clue 3, but Gate-6-Guy, who grabbed the ticket for that flight, is in that one. This means that gate 6 has the South African flight. This means that Gate-6-Guy initially grabbed the SA-Ticket, and that James (who's the only other person stranded) actually wanted to go there.
We can also deduct a few more things based on the language pairings.
Lars speaks both Polish and Dutch, since he's the Non-Zulu-Speaker in the Zulu-triangle.
Bernard speaks Czech and is therefore unable to understand any language of the the Zulu-Dutch-Polish triangle.
Bernard never went to the Czech gate despite speaking Czech, so he didn't want to go to Czechia in the first place (otherwise, he would've known he's at the wrong gate). The only other option left is that he wanted to go to Poland.
The man who's a native Czech speaker also has Poland as the single travel destination option left. So Bernard is actually a native Czech speaker wanting to go to Poland. As we know that the native Czech speaker is PoorSod, aka the person who started out with the Spanish ticket and speaks Irish as a second language, Bernard is fully defined.
We know that James has to have Bernard's ticket to Poland, which means that James doesn't speak Polish himself, which also forces everything about him.
Connor, who is not in the Dutch-Zulu-Polish triangle, only has a single language option left, namely Irish as a first and Spanish as a second language. This also fully solves Connor, who is Mr. Lucky-Irish.
By everything we know, Lars could have grabbed one of three tickets, the South African, Czech or Dutch one.
NL: The Dutch ticket was the one Gate-6-Guy acquired at the first swap, so it wasn't picked up by the person who wanted to go to the Netherlands. But Lars knows Dutch, meaning that he would've noticed if he found himself at the wrong flight. As the person who was approached by Gate-6-Guy in the first swap didn't notice that he was at the wrong gate on their own, this one is out.
SA: This would mean Lars is Gate-6-Guy.
CZ: This would make Lars the man who was approached in the second swap, who actually wanted to go to Spain, and exchanged tickets with Bernard in the third swap. We know that Lars doesn't understand Zulu or Spanish, so Lars wouldn't have seen a difference between the two when he checked out gate 6, and wouldn't have made an additional swap. Therefore, this option is also false.
We can conclude that Lars is Gate-6-Guy who found out that he was at the wrong gate because the writing there didn't look Dutch to him.
After that, it's just a case of filling in the correct squares, everything is forced:
The six men are:
Kellan: From SA, also speaks Dutch, grabbed the Czech ticket and wanted to go to Spain, made his flight
Bernard: From Czechia, also speaks Irish, grabbed the Spanish ticket and wanted to go to Poland, missed his flight
Connor: From Ireland, also speaks Spanish, grabbed the Irish ticket and wanted to go to Ireland, made his flight
James: From Spain, also speaks Czech, grabbed the Polishticket and wanted to go to SA, missed his flight
Philip: From Poland, also speaks Zulu, grabbed the Dutch ticket and wanted to go to Czechia, made his flight
Lars: From the Netherlands, also speaks Polish, grabbed the SA ticket and wanted to go to the Netherlands, made his flight
As for feedback, I really enjoyed this riddle. The only thing I'd change is to make it a bit more clear how the swapping works. It says that people will go to the front desk if they notice that their ticket is wrong, but
Lars found the Dutch flight on his own, and I wasn't sure initially whether he would still go to the front desk or not. Same for the hint the stewardess swapped the tickets of two people at gate 2, it took me a second to understand how there are two men at the same gate. But apart from that, this is a really well crafted riddle