"Shakespere" Pronounced wrong upsets my teacher
I think if you mispronounced 莎士比亚 (Shā shì bǐ yǎ) with a lighter tone, it could become something like 啥是逼呀 (Shà shì bī ya), where 逼 carries a meaning of female's genital which is quite rude. The whole sentence might turn out to be misheard as “啥是逼呀？” which means "What is a pxsxy(逼)?". Then it makes sense for your teacher not explaining that.