"The baby wants to drink beer."
Translation:아기가 맥주를 마시고 싶어해요.
싶어요 is used when talking about yourself, or when asking another person if they want something. 싶어해요 is used when you're talking about someone else in the third person. For example...
저는 먹고 싶어요. = "I want to eat."
너는 먹고 싶어요? = "Do you want to eat?"
제 남동생이 먹고 싶어해요. = "My younger brother wants to eat."