Reported speech is a common feature of English grammar that allows us to convey what someone else has said without quoting their exact words. When using reported speech, certain changes are often required, especially in verb tenses, pronouns, and time expressions. One particular structure that frequently causes confusion is the negative modal verb mustn’t.” Understanding how “mustn’t” changes in reported speech is crucial for accurate communication. This topic explores the rules for converting “mustn’t” into reported speech, clarifies common mistakes, and provides plenty of examples to help you master this aspect of English grammar.
What is Reported Speech?
Reported speech, also known as indirect speech, is when we tell someone what another person said without repeating their exact words. Instead of using quotation marks, the sentence structure changes to reflect that the information is being reported.
For example
- Direct speech She said, “You mustn’t smoke here.”
- Reported speech She said that you must not smoke there.
In reported speech, we usually shift the verb tense back one step (backshifting), adjust pronouns, and modify time or place expressions to fit the new context.
The Modal Verb Must and Its Negative Form Mustn’t
The modal verb must is used to express obligation, necessity, or strong recommendation. Its negative form, mustn’t, means prohibition or something that is not allowed.
- Example with must You must finish your homework.
- Example with mustn’t You mustn’t smoke here.
When converting sentences containing mustn’t into reported speech, it’s important to understand how modals generally change.
How Mustn’t Changes in Reported Speech
Unlike some modals, mustn’t does not have a direct past form. Therefore, when we report speech containing mustn’t, we usually replace it with must not or may not, depending on the context.
- Using must not in reported speechThis is the most common way to report a prohibition or a rule.
- Using may not in reported speechThis is sometimes used to express permission being denied.
However, in many cases, mustn’t in direct speech becomes was not allowed to or were not allowed to in reported speech to clearly express prohibition.
Examples of Changing Mustn’t in Reported Speech
- Direct He said, You mustn’t enter this room. Reported He said that we must not enter that room. Or He said that we were not allowed to enter that room.
- Direct She said, You mustn’t be late. Reported She said that I must not be late. Or She said that I was not allowed to be late.
- Direct They said, You mustn’t touch the equipment. Reported They said that we must not touch the equipment. Or They said that we were not allowed to touch the equipment.
Common Mistakes When Reporting Mustn’t
- Using mustn’t unchanged in reported speech, e.g., He said that you mustn’tÂ… This is usually avoided in formal or written English.
- Replacing mustn’t with didn’t have to – which incorrectly suggests lack of obligation instead of prohibition.
- Failing to adjust pronouns and time expressions appropriately.
Alternative Ways to Report Prohibition Expressed by Mustn’t
Because mustn’t doesn’t have a direct past form, speakers often use other phrases to report prohibitions clearly
- Was/were not allowed to – expresses prohibition in the past.
- Could not or couldn’t – can indicate inability or prohibition, but might be less formal.
- May not – used to express formal denial of permission.
Example
- Direct You mustn’t park here. Reported He said we were not allowed to park there.
- Direct You mustn’t use your phone during the exam. Reported The teacher said that we could not use our phones during the exam.
Backshifting and Time/Place Changes in Reported Speech
When converting direct speech to reported speech, it is important to change time and place expressions to fit the new context.
- Here becomes there.
- Now becomes then.
- Today becomes that day.
Example
- Direct She said, You mustn’t smoke here now. Reported She said that we must not smoke there then.
Reporting Negative Commands with Mustn’t
Mustn’t often appears in negative commands or prohibitions. When reporting these, it’s natural to use verbs like warn, forbid, or order.
- He warned us that we must not enter the building.
- She forbade him to touch the painting.
- The sign ordered that visitors must not feed the animals.
In such cases, the prohibition meaning of mustn’t is retained, but the verb changes to emphasize the command or warning.
Summary of How Mustn’t Changes in Reported Speech
| Direct Speech | Reported Speech |
|---|---|
| You mustn’t enter here. | You must not enter there. Or You were not allowed to enter there. |
| He said, You mustn’t be late. | He said that you must not be late. Or He said that you were not allowed to be late. |
| They said, You mustn’t use your phone. | They said that you must not use your phone. Or They said that you were not allowed to use your phone. |
Practice Exercises
Try converting the following direct speech sentences containing mustn’t into reported speech
- You mustn’t swim in this lake, said the guard.
- She said, You mustn’t talk during the exam.
- They warned us, You mustn’t feed the animals.
- He told me, You mustn’t park here.
Answers
- The guard said that we must not swim in that lake.
Or The guard said that we were not allowed to swim in that lake. - She said that we must not talk during the exam.
Or She said that we were not allowed to talk during the exam. - They warned us that we must not feed the animals.
Or They warned us that we were not allowed to feed the animals. - He told me that I must not park there.
Or He told me that I was not allowed to park there.
Understanding how mustn’t changes in reported speech is essential for accurate and polite communication. Since mustn’t does not have a simple past form, it usually changes to must not or was/were not allowed to in indirect speech. Being aware of this helps avoid common errors and makes your reported sentences clearer and more natural. By practicing the conversion of mustn’t in reported speech, you can improve your English grammar and confidently express prohibitions and rules indirectly.