Are WOHIN and WOHER separable?
In "QUESTION 2" Lesson, it says that "WOHIN" and "WOHER" are separable:
"Furthermore, wohin is separable into wo + hin:<pre>
Wo ist mein Schuh hin? (Where did my shoe go?)</pre>
The same goes for woher (where from):<pre>
Woher kommst du? (Where are you from)</pre>
Wo kommst du her?"</pre>
I asked today my German Teacher, and she said that they are not separable and you cannot separate them? Can someone please explain, and give really strong arguments if they are/are not separable? We had the sentence "Wo kommt die denn her?", and she said that in this sentence its the verb "herkommen" that is separated? Could it be that "WOHER" was separated ?
Good question. (Edit: cross-posted with christian)
Now, I'm certainly no expert on the actual linguistics of German; all I can do is give an opinion as a native speaker, I hope somebody can give a more helpful answer.
"hin" and "her" exist as words of their own, so I have no idea if "Wo kommst du her?" qualifies as a separated "woher", or if it's more like a mere rephrasing; one way or another - scientific definitions aside - you're certainly right that you can say both "Wo kommst du her?" and "Woher kommst du?", or "Wo gehst du hin?" and "Wohin gehst du?".
As for "Wo kommt denn die her?" - it's a fascinating question. My opinion is that the sentence boils down to "woher kommen?" in standard German. In less formal German, however, "wo herkommen?" also works fine.
I also thought it was 'woher/wohin' split up until the OP said that it might be 'herkommen/hingehen' split up which also sounds reasonable, I have no idea either (native speaker).
I suppose since you wouldn't say 'woher kommst du her/wohin gehst du hin' that maybe the 'her/hin' does come from 'woher/wohin' after all? But that's really just a guess, maybe the actual rule is that you have to use 'wo' with 'herkommen/hingehen', who knows... :) Anyway, not much help, sorry, it just goes to show that even native speakers have no idea why something is the way it is... :)
On second thought (thanks to Andu444618 for inspiration, or rather, I'm really just taking their comment a little step further), my bet is on "woher kommen / wohin gehen":
"herkommen" = "to come from somewhere" is, as far as I can see, only used together with "wo?". You don't say, "Ich komme von Deutschland / von der Schule her" (anyway not in correct standard German).
What you can say is e.g. "Er kommt her" ("He's coming over"), "Komm her!" ("Come here!"), etc., but that's a diffferent "herkommen": not "to come from somewhere" ("her" = the other place) but "to come here" ("her" = this place here).
It's similar with "hingehen". You can't say, "Ich gehe in die Schule / nach Spanien hin"; you can say, "There is a concert tomorrow. Ich gehe hin.", but here "hin" equals "there", referring to a thing mentioned earlier (the concert): "I'm going there."
So it seems to me that "Wo kommst du her?" is not derived from "herkommen" (because "herkommen" on its own means something different), but that the "her" is connected to the "wo". I'll still leave the question of whether "woher" is officially separable to the linguists :)