This is the 32nd most frequent Swedish word.
alla
"Alla" means "everyone" or "all" in English.
Here, 'alla' is used as a pronoun meaning 'everyone'.
Alla var där på festen.
Everyone was there at the party.
Here, 'alla' is used as an adjective modifying 'mine vänner', meaning 'all' in English.
Jag bjöd in alla mina vänner.
I invited all my friends.
In this sentence, 'alla' functions as a subject pronoun, equivalent to 'everyone' in English.