He said to me, 'Let's go outside'.

Direct speech is used to report what someone said exactly as they said it. In this case, the direct speech is "Let's go outside." Indirect speech is used to report what someone said without using their exact words. In this case, the indirect speech is "He proposed me that we should go outside."

The following changes were made when converting the sentence from direct to indirect speech:

• The quotation marks are removed. The imperative mood ("Let's go") is changed to the indicative mood ("he proposed").

• The first-person plural pronoun ("we") is changed to the first-person singular pronoun ("me") because the speaker is reporting what someone said to them. The modal verb ("should") is added to express the speaker's suggestion.

• The indirect speech is a more formal way of reporting what someone said. It is often used in writing, especially in academic or professional settings.