I think in English, gutter would insult boys.
The teenage years are interesting; the boys can't get their minds out of the gutter, and the girls can't take their minds off "gutter".
Isn't that sentence means also "Boy and girl" as singular? What part of the sentence determines that this is plural?
The singular version would be "gutt og jente", so it's the suffix "-er" that makes them plural.
You should be able to hear an 'r' sound in 'jenter' compared to an open vowel sound at the end of 'jenta'
It's not an r sound like in American English, it's a flap. It sounds like a soft 'd' sound. In this particular sentence I find it easier to hear in 'gutter' than in 'jenter'. The 'a' in 'jenta' should sound like the 'u' sound in 'cup'.
In practice you can often tell from context which word it should be - it's a little harder in an isolated phrase like this
How do I distinguish singular and plural? Is it by the suffix -er or...?
Yes, although with a word like jente that already ends in -e you just add -r
og would mean 'and' so what would 'or' be? I don't know what it is but every time I see this my mind instantly goes "Oh, its obviously boys or girls" --- very annoying because I cant seem to get past it.