'long' (time) and 'far' (distance) are both accepted, but they have different meanings? Does 'langt' cover both of these meanings?
No, "langt" is distance. "lenge" is time.
But "long" in English can be used about time and distance?
"How long" is definitely time and "how far" is definitely distance, not interchangeable at all for me. I translated this sentence "How long can you run?" and was surprised to see "How far can you run?" listed as an alternative answer because for me they have completely different meanings.
In this context though I would agree that in English "long" would mean time. "Long" as in length is usually an adjective, not an adverb.
Technically the proper way to say it would be to use "far" for distance but it can be understood easily if referring to distance by "long."
Generally, no. However, there are instances where one could use "long" in describing both. Duration and measurements for example.
"For how long can you run" sounds more natural to me, but was not accepted. Can someone explain to me why, please? :)
Because it is referring to distance traveled rather than amount of time running. Does that make sense?
I believe it is 'langt' because it is an adverb.
The adjective 'lang' means 'long', adding 't' changes the adjective to the adverb 'langt' and it now means 'far'.
Noen eksempler fra ordboka mi: 'Lang i ansiktet' (long in the face) meaning dejected, glum. Vs 'Langt borte' meaning far away.