Direct and indirect speech, also known as reported speech, is a way of conveying what someone else has said. It is used to report or relay information, statements, questions, or commands made by someone else. In English grammar, there are certain rules and changes that need to be followed when converting direct speech into indirect speech.

Direct Speech:
Direct speech is the exact words spoken by a person and is usually enclosed in quotation marks. For example:
- She said, "I am going to the park."

Indirect Speech:
Indirect speech is when we report or paraphrase what someone else has said without using their exact words. It does not require quotation marks. For example:
- She said that she was going to the park.

Changes in Tense:
When converting direct speech into indirect speech, the tense of the verb often needs to be changed to reflect the reporting of past events. The following changes occur:

- Present Simple changes to Past Simple: "I am going" becomes "She said that she was going."
- Present Continuous changes to Past Continuous: "I am eating" becomes "She said that she was eating."
- Present Perfect changes to Past Perfect: "I have finished" becomes "She said that she had finished."

Changes in Pronouns:
Pronouns also undergo changes in indirect speech to reflect the perspective of the reported speaker. The following changes occur:

- First-person pronouns (I, me, my) change according to the subject of the reporting verb: "I am happy" becomes "She said that she was happy."
- Second-person pronouns (you, your) change according to the object of the reporting verb: "You are late" becomes "She said that I was late."
- Third-person pronouns (he, she, it) remain the same unless there is a change in the reported subject: "He is tired" becomes "She said that he was tired."

Changes in Time and Place:
When reporting speech, there may be changes in time and place references. For example:

- "I will come tomorrow" becomes "She said that she would come the next day."
- "I am here" becomes "She said that she was there."

Reporting Verbs:
Reporting verbs such as say, tell, ask, etc., are used to introduce indirect speech. These verbs are often followed by a noun clause or the conjunction 'that'. For example:

- She said, "I am happy" becomes "She said that she was happy."
- He asked, "Where are you going?" becomes "He asked where I was going."

In conclusion, direct and indirect speech are important concepts in English grammar to report what someone else has said. These changes in tense, pronouns, time, and place are necessary to convey the reported information accurately. Practice and understanding these rules will help in effectively using direct and indirect speech.