Learning to talk about obligation is super important in English! When we talk about obligation, we’re saying what is necessary or required. This lesson will help you understand and use the words must and have to to express obligation clearly and confidently. This is perfect for A2 English learners who want to improve their practical English speaking skills. Let’s get started!

What is Obligation in English?

Obligation means something you need to do or something that is necessary. Think about rules, responsibilities, and things that are important to do. For example:

• If you are driving, you must stop at a red light. (It’s the law!)
• I have to go to work tomorrow. (It’s my job!)

Understanding how to express obligation is key for everyday conversations and understanding instructions in English. It’s a fundamental part of functional English, and we’ll focus on how to use it in speaking.

How to Talk About Obligation: ‘Must’ and ‘Have to’

In English, we often use the words must and have to to talk about obligation. They are similar, but there are some important differences. Let’s explore them!

Using ‘Must’ for Obligation

We use must to talk about obligations that come from the speaker’s own feelings or strong personal opinions, rules made by the speaker, or when something is very important and necessary in their opinion. It often shows a stronger, more internal obligation.
Here are some examples of using must:

• I must remember to call my mum today. (It’s important to me.)
• You must be quiet in the library. (This is the rule here, and I’m telling you.)
• We must try this new restaurant! (I really want to, and I think it’s important we do.)

Notice how ‘must’ often feels more like a personal feeling or a rule set by the person speaking. It’s a strong way to express obligation.

Using ‘Have to’ for Obligation

We use have to to talk about obligations that come from outside of the speaker. This could be rules, laws, routines, or someone else telling you something is necessary. It’s often about external obligations or necessities.
Here are some examples of using have to:

• I have to wear a uniform at my school. (It’s the school rule.)
• You have to pay for your ticket before you get on the bus. (It’s the rule for everyone.)
• She has to work late tonight. (Her boss told her it’s necessary.)

With ‘have to’, the obligation usually comes from someone or something else – a rule, a law, a person in authority, or a general necessity.

‘Must’ vs. ‘Have to’: What’s the Difference?

While both must and have to talk about obligation, the source of the obligation is a bit different:

• Must: Often comes from the speaker’s internal feeling, personal rule, or strong opinion. It’s more subjective and can feel stronger or more urgent.
• Have to: Usually comes from an external source – rules, laws, someone else’s authority, or general necessity. It’s more objective and about external requirements.

Think of it like this: must is often what you tell yourself or what you strongly believe, and have to is often what someone or something else tells you or what is generally required.
Let’s look at a few more examples to see the difference in context:

• Example 1:
  • “I must eat healthier.” (My personal goal, my strong feeling.)
  • “I have to eat my vegetables.” (My mum tells me to, or it’s a general rule for good health.)
• Example 2:
  • “We must be on time for the meeting.” (I think it’s very important to be punctual.)
  • “We have to be on time for the meeting.” (The boss said it’s essential, or it starts at a fixed time.)

In many everyday situations, you can use either must or have to, and people will understand you. However, understanding the nuance will make your English more precise and natural, especially when speaking!

Negative Obligations: ‘Mustn’t’ and ‘Don’t have to’

To talk about negative obligations (things you are not allowed to do or things you don’t need to do), we use mustn’t and don’t have to.

‘Mustn’t’ – Prohibition (Strongly Not Allowed)

Mustn’t means it is forbidden or strongly not allowed. It’s a strong negative obligation.
Examples of mustn’t:

• You mustn’t run in the school hallways. (It’s a very important rule.)
• You mustn’t touch that! It’s dangerous. (Strong warning.)
• We mustn’t forget our passports when we go to the airport. (It’s very important not to forget.)

Mustn’t is a strong way of saying “do not do this!”.

‘Don’t have to’ – No Obligation (Not Necessary)

Don’t have to means it is not necessary or there is no obligation. You can do it if you want, but it’s not required.
Examples of don’t have to:

• You don’t have to come to the party if you are tired. (It’s optional, not required.)
• I don’t have to work on Sundays. (It’s my day off.)
• We don’t have to buy milk; we already have some. (It’s not necessary to buy more.)

Don’t have to means you have a choice; there’s no obligation or necessity.

Let’s Practice Talking About Obligation!

Now it’s your turn to practice using must, have to, mustn’t, and don’t have to! Complete the sentences below. Choose the best word to express the obligation in each situation.

Exercise 1: Fill in the blanks with ‘must’ or ‘have to’.

1. I ___ wake up early tomorrow. I have an important meeting.
2. You ___ wear a seatbelt in the car. It’s the law.
3. We ___ remember to buy bread when we go to the supermarket. We need it for sandwiches.
4. Students ___ be quiet during the exam. It’s a school rule.
5. She ___ study hard if she wants to pass the test.

Exercise 2: Rewrite the sentences using ‘mustn’t’ or ‘don’t have to’.

Change these sentences to express the opposite meaning using ‘mustn’t’ or ‘don’t have to’.

1. It is necessary to shout in the library. (Change to: It is forbidden…)
2. You need to pay to enter this museum. (Change to: It’s not necessary…)
3. It’s required to talk loudly on the phone in the cinema. (Change to: It’s forbidden…)
4. You need to finish all the food on your plate. (Change to: It’s not necessary…)
5. It’s necessary to be late for school. (Change to: It’s forbidden…)

Answers

Answers for Exercise 1:

1. I have to wake up early tomorrow. I have an important meeting. (External necessity – meeting)
2. You must wear a seatbelt in the car. It’s the law. (Often ‘must’ is used for general rules and laws, but ‘have to’ is also acceptable here. ‘Must’ can feel slightly stronger in this context.)
3. We must remember to buy bread when we go to the supermarket. We need it for sandwiches. (Personal importance, strong reminder to ourselves.)
4. Students must be quiet during the exam. It’s a school rule. (School rules, but also can be seen as a strong internal rule for the exam environment.)
5. She has to study hard if she wants to pass the test. (External necessity – requirement to pass the test.)

Answers for Exercise 2:

1. You mustn’t shout in the library.
2. You don’t have to pay to enter this museum.
3. You mustn’t talk loudly on the phone in the cinema.
4. You don’t have to finish all the food on your plate.
5. You mustn’t be late for school.

Practice Speaking About Obligation with Lingofrnd

Understanding grammar is important, but speaking is key! To really master talking about obligation, you need to practice speaking. Lingofrnd.com is an amazing AI spoken English teacher that can help you practice using must and have to in real conversations. You can improve your spoken English and build confidence in expressing obligations in different situations.
Want to practice anytime, anywhere? Download App and start speaking English with Lingofrnd today! Practice making sentences about your daily obligations, rules at home or school, and things you feel are important.

Conclusion

Congratulations! You’ve learned how to talk about obligation in English using must and have to! Remember the key differences and keep practicing. The more you use these words in your speaking and writing, the more natural they will become. Keep learning and keep speaking!