the way 用疑问

That is the way how he spoke.

为何这句话是错的？ 为何只能说That is how he spoke. 呢？

how不可以引导定语从句，但可以引导名词性关系分句。That is the way how he spoke.这个句子中how he spoke 为定语从句，how要改为that（或省略that）/ in which (正式）。在That is how he spoke中，how he spoke为名词性关系分句。how=the way that/in which。