Deaf people are sometimes treated as being mentally deficient.

耳聋的人有时被看作智力不健全。

《牛津词典》

If you have a slurred voice, people are likely to treat you as mentally deficient: Does he take sugar?

说话不清楚，人们很可能把你看成智力有缺陷：他是在吃糖吗？

youdao