Direct and indirect speech, also known as reported speech, are two ways of expressing someone else's words or thoughts. In direct speech, the exact words of the speaker are quoted, while in indirect speech, the speaker's words are reported or paraphrased.

Direct Speech:
In direct speech, the exact words of the speaker are enclosed in quotation marks and reported as they were spoken. The reporting verb is usually in the present tense.

Example 1:
Direct Speech: She said, "I am going to the park."
Indirect Speech: She said that she was going to the park.

Example 2:
Direct Speech: He said, "I will be there tomorrow."
Indirect Speech: He said that he would be there the next day.

Example 3:
Direct Speech: "I love playing the piano," she said.
Indirect Speech: She said that she loved playing the piano.

Indirect Speech:
In indirect speech, the speaker's words are reported or paraphrased without using quotation marks. The reporting verb is usually in the past tense.

Example 1:
Direct Speech: "I can't come to the party," he said.
Indirect Speech: He said that he couldn't come to the party.

Example 2:
Direct Speech: "I have finished my homework," she said.
Indirect Speech: She said that she had finished her homework.

Example 3:
Direct Speech: "I want to travel the world," he said.
Indirect Speech: He said that he wanted to travel the world.

Key Differences:
- In direct speech, the exact words of the speaker are quoted, while in indirect speech, the speaker's words are reported or paraphrased.
- In direct speech, the reporting verb is usually in the present tense, while in indirect speech, the reporting verb is usually in the past tense.
- In direct speech, quotation marks are used to enclose the speaker's words, while in indirect speech, quotation marks are not used.

Advantages of Direct and Indirect Speech:
- Direct speech allows for the precise quoting of someone's words, capturing their tone and emphasis.
- Indirect speech allows for the reporting of someone's words without the need for quotation marks, providing a more concise and summarized version of the original statement.

In conclusion, direct and indirect speech are two ways of reporting someone else's words or thoughts. Direct speech involves quoting the speaker's exact words, while indirect speech involves reporting or paraphrasing the speaker's words. Both forms have their advantages and are used in different contexts to convey information accurately and effectively.