One sign of multiple sclerosis is losing the ability to speak clearly.

VOA: special.2009.01.06

But, also, there are genetic disorders, some falling under the rubric of what's known as "Specific language impairment," where children are born without the same ability as the rest of us to learn to speak.

但被叫做"特殊言语损伤"的遗传障碍,也能使你失去语言能力,儿童出生便不具有,我们其他人所具有的学习说话的能力

耶鲁公开课 - 心理学导论课程节选

Yeah! Well, I mean, I think for sure, the best way to improve your ability to speak any language

行！我认为，我觉得也一定是这样，最好的提高语言能力的方法，

想征服英语的话 - SpeakingMax英语口语达人