The general idea behind Duo is that you're supposed to learn like children learn – by seeing lots of examples. Clearly that isn't enough, and we do try to give some explanations, but the use of prepositions is very hard to explain concisely, and the cluster till, åt, and för are among the hardest ones.
When it comes to till frukost 'for breakfast' I'd say it's just a set expression so that in reality there's really no point in trying to analyze it, although some of us can't resist trying to do so anyway, which is why I mentioned the 'purpose/goal' examples. One could also analyze it as the 'addition' meaning that till sometimes has.
Below just a VERY short version of the most typical uses of till vs för
till is most typically used
1) with movement to a goal jag åker till Kina 'I am going to China'
2) when giving something to someone jag ger en bok till mamma 'I am giving a book to my mom' – same with jag köper en bok till mamma 'I am buying a book for mom'
för is most typically used
1) whenever there's an 'audience': jag berättade för honom 'I told him', jag sjöng för henne 'I sang to her', jag visade den för honom 'I showed it to him'
2) in 'exchange' situations: jag ger dig 10 kronor för den 'I'll give you SEK10 for it'
3) 'concerning' det är svårt för oss 'it's difficult for us'
There are tons of other more special uses, but if you want an overview to start with, I think you should keep these concepts in mind, and try to build from these.
I don't know if this can help anyone, but till and för are basically like "à" and "pour" in French. They're very similar and can be used in similar situations, and therefore are quite confusing for people learning French.
While in English you can only say "we eat eggs FOR breakfast" in French you can say both "Nous mangeons des oeufs AU petit-déjeuner" (au means à + le) or "nous mangeons des oeufs POUR le petit-déjeuner" so using till in this sentence isn't as confusing for French ppl as it is for english ppl. Plus, in Swedish you would use för to say "jag sjöng för henne" (I sang to her) well same in French, we won't say "Je chantais à (to) elle" but "Je chantais POUR (for) elle."
So if you have some knowledge in French maybe seeing it that way could help. Moreover, this isn't the only ressemblance between Swedish and French or other European languages, like if u're used to the pronouns (possesives or relatives) in either French or Italian, learning them in Swedish will seem quite easy and familiar. Hope all of this makes sense.
Can't tell you how happy I am that you said this, my native language is English but I lived in Portugal for over 10 years so i'm fluent in Portuguese and know quite abit of French since they're simular languages, its the same thing in portuguese. That helps me so much! I'm learning Swedish from an English brain, if I thought of Swedish with my portuguese/french brain sometimes might actually help me out in certain situations! :D
Nous mangeons oeufs au petit-déjeuner - Nós comemos ovos ao pequeno-almoço.
Je chantais pour elle - Eu cantei para ela.
Oh I'm so glad you found it helpfup :))
Ikr!! Sometimes learning a language can be easier if you look at it through another language. I'm fluent in both English and French and I sometimes feel more comfortable learning a language using one instead of the other. When I'm learning a latin language like Italian I don't even think twice : I use French, and I'm saving so much more time than if I was learning it in English. I have to say Swedish is a little more complicated because of its similarities to both germanic and latin languages haha...
Good luck with your languages Ann :D
Well yeah of course you can say We eat eggs AT breakfast (duh). Just like you can use any other preposition you like "She made an announcement DURING breakfast" or "She wrote an essay ON breakfast". But the meaning is different for each preposition and this whole thread is about eating smth [food] FOR breakfast. So you can't say AT in this case. If we were focusing on the place or time like you said then yes AT would be appropriate.
Both tills and till are acceptable in this sense before a noun, but it isn't recommended to use till this way to start a subclause.
till i morgon and tills i morgon both work, but only Vi håller på tills imorgon 'We're keeping at it until tomorrow'. (or like here, tills frukosten kommer)