Jag ska leta tills jag hittar den = I will be looking until I find it
In this sentence, we're talking about the fact that I will be continuing to look for something until certain criterion (me finding it) is met. I will then stop looking.
Jag ska inte gå förrän jag hittar den = I will not leave until I find it
In this sentence, we're talking about a future action (me leaving) that will begin to happen once the same criteron as above is met (me finding it). I will leave as soon as I find it.
The difference is thus whether the action stops or starts when the criteria are met. Does that make it clearer?
Man you're fast. There is no reply button under your last post so I use the one under your former comment (and give myself a like-point for the correct order).
It's perfectly clear to me now that “förrän” is never by itself, but needs “inte” or a other negating word.
In my second example, would it be correct Swedish if 'förrän' is replaced by 'innan'?
Jag ska leta innan jag går - I will be looking before I leave
Yes, "Until" or "Tills" in this lesson is not a preposition. What do you think was the object of the preposition? The clause "you find it" follows "until" and the clause "du hittar den" follows "tills" here. I know that "until" can be either a preposition or a conjunction, but the dictionary that you are using does not acknowledge that, nor for the Swedish. https://en.wiktionary.org/wiki/tills
The following better dictionary recognizes "tills" as a conjunction.
Perhaps it is important to note that this is not a complete sentence and in such a situation the conjunction introduces a clause. There is not a rest of sentence for it to connect that clause to.
No, because "tills du hittar den" is a subclause. In the subclause, the V2 rule doesn't apply.
Imagine the full sentence, it could be something like "Vi ska stanna här tills du hittar den."
Words like inte and gärna, for example, come before the verb in the subclause, unlike in the main clause (because of the V2 rule). So, for example, "Jag ska gå inte om inte du kommer" meaning "I'm not going if you don't come."
And if you just asked me a question like "Ska du gå?" I may just answer "Nej, om inte du kommer," meaning "No, unless you come." or "No, if you don't come." I like how the structure is similar to older English... "I shall go not if not you come..."
BTW, I'm a Swedish learner myself, so I could be wrong here! I'm sure someone will correct if I'm completely wrong (always possible)