어서 부르다

sing it, or call it something

부르다 is both singing and calling something by a name, and both are here. The naming use is the more useful: 줄여서 부르다 "call it by a shortened form", as in 일상적으로 '일쓰'라고 줄여서 부르기도 해요, and 붙여서 부르다, saying two words run together. The singing use covers 따라서 부르다 "sing along" and 와서 부르다 "come in and sing it". Whether what follows is a song or a name decides which sense applies.