* Urge someone to hurry up: "Yalla, we're late!"
* Encourage someone to start something: "Yalla, let's eat!"
* Express excitement or enthusiasm: "Yalla, let's go to the beach!"
"Yalla" is often used in informal situations and can be used by both men and women.
It's a very useful phrase to know if you're learning Arabic, as it can be used in a variety of contexts.