This is the 128th most frequent Swedish word.
länge
For a long time.
In this sentence, 'länge' is used to denote a long duration of time, indicating that the speaker has not seen the person for an extended period.
Jag har inte sett dig på länge.
I haven't seen you in a long time.
In this context, 'länge' describes a prolonged action or state, emphasizing the extended duration for which he remained awake and active.
Han stannade uppe länge för att arbeta.
He stayed up late to work.
Here, 'länge' is employed to inquire about the duration of time for which the waiting will occur, highlighting its usage in questions related to time span.