Two weils
After weil, the verb goes to the end. That is still the rule. But listen to any German conversation and you will also hear the verb in second position, as in a main clause. This is not a learner error that natives make by accident. It is a separate spoken construction with its own sound and its own limits.
Same reason, two constructions
Verb last: standard
Ich komme später, weil ich noch arbeiten muss.
I'll be late because I still have to work.
correct in speech and in writing
Verb second: spoken
Ich komme später, weil – ich muss noch arbeiten.
I'll be late, 'cause I've still got work to do.
speech and chat only, with a small pause after weil
What makes verb-second weil different
With verb second, weil behaves less like a conjunction and more like denn: it links two independent statements. That has three audible and grammatical consequences.
Typical spoken uses
Die sind bestimmt schon da, weil – da steht ihr Auto.
They must be here already, because there's their car.
evidence for a guess
Lass uns lieber gehen, weil – das dauert hier ja ewig.
Let's go, this is taking forever anyway.
a particle like ja fits the main-clause order
obwohl as a correction
With verb second, obwohl changes its job. It no longer concedes a fact; it takes back or qualifies what you have just said, like English sentence-initial although or mind you. It usually starts a new breath, often followed by a pause. wobei works the same way and is even more common in this role.
Ich komme mit, obwohl ich eigentlich keine Zeit habe.
I'll come, even though I don't really have time.
verb last: concession, you are coming
Ich komme mit. Obwohl – ich habe eigentlich keine Zeit.
I'll come. Although, actually, I don't have time.
verb second: you are reconsidering
Das Hotel war super. Wobei – das Frühstück war eher mau.
The hotel was great. Mind you, breakfast was pretty poor.
wobei with verb second, a typical correction
In writing: weil with verb last, or denn
In any written text above a chat message, verb-second weil counts as an error. If you want two independent statements, the written conjunction is denn, which takes verb second by design.
Der Termin wird verschoben, weil die Referentin erkrankt ist.
The appointment is being postponed because the speaker is ill.
Der Termin wird verschoben, denn die Referentin ist erkrankt.
The appointment is being postponed, as the speaker is ill.
