We usually say说的话rather than写的话. I found some kinds of examples from有道,maybe can help you. Examples 1.我相信他的话。 I trust his word. （他的话=his word） 2.她误解了我所说的话。 She misunderstood what I said. （ 我所说的话=what I said) 3. 这是我从他说的话中推断出来的。 This is what I gathered from his speech. （他说的话=his speech) 4. 我的话并不是针对你们所有人的。 My remarks were not directed to all of you. （我的话=my remarks） In addition Sometimes we say”如果...的话”,as same as”if” example 如果需要的话，可以制造一个理由。 Make up a reason if you have to. （In this sentence，的话can be omitted,like 如果需要，可以制造一个理由,I think the difference is when you use”的话”,the sentence is more colloquial.）