You could look at what it does but babies are not very coordinated or skilled so you need to use clever methods.

你可以观察婴儿,但婴儿不怎么配合,或者说他们的言语技能并不熟练,所以你必须要用精巧的方法才能做到

耶鲁公开课 - 心理学导论课程节选

Yeah, but I think it's also an important skill. You need to be able to express what you know

难，但是我也觉得这是一种重要的技能。你必须能够把你知道的表达出来，

沟通很重要 - SpeakingMax英语口语达人