Kind of and sort of are very common expressions in speaking. They soften other words and phrases so that they do not appear too direct or exact. Kind of is more common in American English. Sort of is more common in British English:
He’s kind of jealous that they have become such good friends.
I’m sorry but she’s just kind of lost interest in buying the car.
They said it was a chalet but it was more like a sort of wooden hut.
She’s spent the whole year sort of travelling around the world.