Toddlers need to learn to take turns. It is not an innate skill. At this age, toddlers are all about themselves and their own needs. It is hard to think of the needs of others and appreciate the fact that other children need a turn on the swings or a turn while playing a game.
Conversation is tiny exchanges of turns. Your toddler has likely been engaging in this as soon as they started babbling back and forth with you. With a little bit of intention, this is a fairly easy concept to teach, but your toddler will need a lot of reminders and reinforcements!
By taking the time to teach turn-taking you are providing your toddler with a great social skill!