jag eller mig
Hello, today I've put a caption on a photo: "me and some stones" and I was wondering how to say it in Swedish. I thought that it must be "jag och några stenar", but google translate is adamant that it is "mig och några stenar".
After a search, I found that other people have had similar questions, like: do you say "han är bättre än mig" or "han är bättre än jag"?
Yet another question, which one is correct: "jag och du är bästa vänner" or "mig och dig är bästa vänner"? Both of them seem correct to me.
This is a good one. Jag = I (nominative). Mig = me (object). As in English (think of "my friends and I" or "me and my friends"), these can sometimes be a bit messy, but in most cases only one is correct.
For the caption, it has to be "Jag och några stenar". "Mig" would mean that you are an object of something. So if the whole caption reads "Det här är ett foto av mig och några stenar", then it is "mig", but on its own, just jag.
It used to be that comparative sentences like "bättre än" had to take the nominative, ie. "jag". The idea is that there is an unspoken (although there's nothing stopping it from being spoken) "är" at the end of the phrase: "Han är bättre än jag (är)". He is better than I am. Just like you could say either "He is better than I am" or "He is better than me" in English.
(Personally, I prefer the "bättre än jag" variant, and many people do, but the "bättre än mig" variant has become so common in Sweden than there are actually people who think the former is wrong...)
You also have to watch out with sentences such as "Du åt mer än mig". Technically, it means "You ate more than me", ie. you ate me and something/someone else, too, because you're using the object form. The version "Du åt mer än jag" is impossible to misunderstand: we both ate, but you ate more than I did.
For the last one, it again has to be "Jag och du är bästa vänner", because jag är and du är. There is no object in the sentence. But "Jag och du är bästa vänner med henne", there you have an object again.
Actually "me and my friends" isn't proper, but it's colloquial. It sounds weird to me to say "the fireman saw my friends and me", even though that's the proper way to say it. If you ask an average American how they would say it, they'd probably say "the fireman saw me and my friends" since that's just how we say it, but it's not right.
It's more respectful to put others first, but there is nothing grammatically wrong with "the fireman saw me and my friends."
In English, my pet peeve is the hypercorrection "the fireman saw my friends and I". :-) I hear this quite a lot nowadays in American media.
(My other pet peeve is people who seem to think "hypercorrect" means "really correct"...)
I did say it was messy in both languages. :-) See Ezkertias answer below, though.