Direct quotations are quotations that are word for word identical to what the original speaker said. In English we use quotation marks to signal that a quotation is direct.

He said: "The sky is blue."

Indirect quotations convey the meaning of what someone said, without exactly saying the same. We can use the word that to signify that a quotation is indirect.

He said that the sky was blue.

For direct quotations, Japanese also uses something like quotation marks. They look a bit different though, and are called 鉤kagi括kak弧ko.

In indirect quotations, we don't use 鉤kagi括kak弧ko. Indirect quotations are always paraphrased using the plain form, even if the original speaker actually used the polite form. So when using indirect quotation the sentence above would change as follows.

Note that the particle と is used after both direct and indirect quotations. And secondly, note that though in normal sentences the topic particle は appears only once, in direct quotations it's okay to use the particle both in the quote and in the main sentence, while in indirect quotations it's more common to use が to mark the subject in the quoted part.

Below are two sentences that describe the same event, the first one using a direct quotation and the second one using an indirect quotation.

Note firstly that we replaced the word 私 with 自分 in the indirect quotation, because it would otherwise be unclear if the 私 referred to the speaker or the person spoken about.

Secondly, note that though we need to use the plain form of the verb in the indirect quotation, we did change 母 to お母さん in the second sentence. So in indirect quotations we apply appropriate politeness levels when talking about someone, even though we put the main verb of the quotation in the plain form.

We do not change the politeness of direct quotations though, as direct quotations need to be word for word identical to what the original speaker said.

Breakdown of to wo simeru.