"He comes here every day."
Translation:Han kommer hit varje dag.
"Hit" and "Dit" are used when someone or something is moving towards "Here" or "There".
"Han kommer hit"
"Han gick dit"
"Här" and "Där" refer to the state of someone or something being "Here" or "There".
"Han står där"
"Han var här"
"Han kommer att vara här"
In a previous sentence, I was marked wrong for typing "åker du dit ofta," and I was told "åker du ofta dit" was correct; are there rules on which adverbs come before others that makes this current sentence not "Han kommer varje dag hit"?
When studying German at school we were told word order should be time-manner-place (as opposed to the English place-manner-time). That is, the Germans would say "I went yesterday with my parents to the park" rather than "I went to the park with my parents yesterday". Maybe Swedish follows the same pattern? (Though i can't find a reference... Perhaps a native could confirm/correct me)
It's definitely not like in German. We would say Jag gick till parken med mina föräldrar i går or I går gick jag till parken med mina föräldrar or maybe (a little less likely but still ok) Jag gick till parken i går med mina föräldrar. Putting i går before med mina föräldrar (as in Jag gick i går med mina föräldrar till parken) may not be grammatically wrong per se, but it's even less likely. It might make it sound like you dumped them there or something.
In the case of Åker du ofta dit?, that word order might be a little more common, but actually Åker du dit ofta? is also totally OK, and it's been an accepted answer for at least six months, maybe longer. (the original question here is a year old, so we probably just hadn't added enough answers at that point).
However Åker du varje dag hit? sounds off. I'd probably think that someone who said that was not a native speaker of Swedish.
Giving rules for the placement of adverbs is among the hardest things in Swedish grammar. I said a little bit about it in the word order topic here: https://www.duolingo.com/comment/8970470 but that's far from exhaustive. Time adverbials like to go at the end (or start) of the sentence. With ofta, you could probably see it either as a time adverbial or as a satsadverbial 'sentence adverbial'. A sentence adverbial modifies the whole sentence and those usually go in the 4th place (like ofta in Åker du ofta dit?).
varje dag and i dag are clearly time adverbials, not sentence adverbials, so while Åker du ofta dit? is fine, "Åker du i dag dit?" sounds off.
Note: when I say above that some things sound wrong: you might still hear that said in the spoken language in the right context and with the right intonation. But in order to give any kind of rules at all, we need to look at normal contexts and normal intonations.