And I think many parents believe that if they didn't persist in using these things their children would never learn to speak.

我相信很多父母认为,如果他们不坚持使用这些东西,他们的孩子将永远也学不会说话

耶鲁公开课 - 心理学导论课程节选

You learn best by speaking, and so when you do have different...

通过说话你学得最好，所以当你真的有不同的……

哈佛的讨论文化 - SpeakingMax英语口语达人