When telling Marin that you weren’t listening, in J she says 上の空 (uwa no sora) which is literally “above the sky” and means “absentminded,” so “head in the clouds” is a perfect translation.
In Japanese Marin says that she wants to go see Link’s hometown someday. Considering her following embarrassment, it seems like this is supposed to be akin to a confession, but “I want to see your hometown” isn’t really a common sentiment in English, so the line was changed.
The end of Marin’s speech was tweaked in E between GB/C and Switch, most likely to make it sound a little more natural. (The J is unchanged.)
When you get Marin, the Japanese text technically says you’re borrowing her, while the English just goes with the standard phrasing from when you get an item.
When talking to the kids as Marin follows you, they do a slight variation in Japanese of their standard “I dunno” line that’s basically something like “I’m a kid, so let’s just say I don’t have a clue and leave it at that.”
When falling down the well with Marin, she gets an extra line on Switch declaring her surprise.
Incidentally, she speaks very colloquially here in Japanese, using びっくらこいた (bikkura koita) instead of the standard phrase びっくりした (bikkuri shita).
When you take Marin to the Trendy Game, she’ll want to play. But if you refuse her, the second choice in Japanese changes to しょうがない (shou ga nai) which is basically “Guess I’ve got no choice.”
When you break a pot, Marin says “Aaah! You mustn’t do that!” in Japanese, but in English she calls Link a “bad boy”.
Also, if you continue breaking pots, she’ll suddenly start egging you on. This is true in the GB/C version too, though you need to be in a house with two screens and a lot of pots to be able to get it to trigger, it seems.
Similarly, she’ll initially protest when you hurt a chicken…
…but do it enough times, and she’ll snap. Though once again, she’ll immediately deny that she said anything.
She also comments when you go into a dungeon…
…and when you come out of one.
AND she says something different if you come back out with low hearts. On J Switch she gets extra lines basically saying “I told you so!” and then once again pretending that she didn’t say anything.
She also has unique dialogue when digging holes (showing a bit of her manic side again), and when checking drawers…
…AND playing the ocarina (once again doing the “I didn’t say anything” shtick).
Although she scolds Link for hurting chickens and breaking pots, she won’t say a word when you steal something from the shop. Some of her text gets funnier with Link’s new name, though.
That’s it for Marin. Next we’ll go to the desert and beyond!