Can I use "can" instead of "may" when asking for permission?

Yes, in everyday conversation. Most native speakers say "Can I ask you a question" instead of "May I ask you a question." May sounds more formal and respectful, so use it in professional settings or with someone you want to be especially polite to. But both are understood and both are correct.

What is the difference between "must" and "have to"?

Must shows obligation in general or a rule that comes from authority. Have to often sounds more personal. "You must wear a uniform" is a rule. "I have to go to work early tomorrow" is personal. In everyday speech, English speakers use have to more often than must, but they mean almost the same thing.

Why do English speakers sometimes say "can" for permission but it sounds like ability?

Context tells you which one is meant. "Can I use your computer" is asking permission, even though can also means ability. The listener knows from the sentence that you are not asking if you are physically able to touch the computer. Native speakers understand both meanings at once and pick the right one from how you use it.

Should I practice modal verbs alone or with someone?

With someone. Modal verbs only make sense when you are actually communicating. Practicing alone teaches you rules. Speaking with another person teaches you when and why to use them. A language exchange partner or a small group class gives you that real practice where you hear the words and feel the difference between them.

Must vs Can vs May: How to Use English Modal Verbs Correctly

Modal verbs like must, can, and may overlap so much in English that most learners mix them up. The difference comes down to who is in control: must is a rule or obligation, can is an ability or permission you give freely, and may is a polite request for permission. Once you see this pattern, they stop being confusing.

What does "must" really mean?

You use must when something is a rule, a legal requirement, or a serious obligation. The obligation comes from outside, from a law or an authority figure. "You must wear a seatbelt" means the law demands it, not a suggestion. "You must submit your essay by Friday" means your teacher has set a deadline. "You must call your mother" might mean your family expects it.

Must carries weight. It is not optional. When you say must, you are telling someone they have no real choice.

When do you actually say "can"?

You use can to show ability or to give permission. "You can use my phone" means you are giving someone the right to use it. You own the phone, so the permission comes from you. "I can speak French" means you have the ability to do it. "Can you help me" is a question about whether someone is able to help.

Can is loose and open. When you give permission with can, you are being generous with your own thing. The other person does not feel trapped. They feel trusted.

Where does "may" fit in?

You use may for a polite request for permission. "May I ask you a question" is formal and respectful. It is a way of asking without demanding. "May I borrow your pen" is softer than "Can I borrow your pen," though both work.

May is the opposite of must. Must is an obligation placed on you. May is a gentle request you are making, hoping the other person will say yes. In a real conversation, English speakers use can and may almost the same way when asking for permission, but may sounds more formal and respectful.

Why learners get stuck

The real confusion comes because can and may both involve permission, and because some rules sound like obligations. You might hear "You can only enter if you have a ticket" and wonder if that is can or must. It is actually can with a condition attached. The rule is that without a ticket, you cannot enter. The rule exists, but the word is still can.

The way to keep them straight is to ask yourself: Is someone forcing me to do this, or am I choosing, or am I asking politely? If you are forced, it is must. If you are choosing or being asked, it is can or may.

The only way to truly learn modal verbs

Reading about must, can, and may teaches you the rules, but speaking them teaches you the feeling. When you use them in real conversation with someone, you hear how they land in a sentence. You notice that must sounds heavy, can sounds natural, and may sounds formal.

PBC Languages runs live classes in very small groups, with a maximum of 4 students, so you actually get speaking time instead of sitting silent. Your teacher will correct you in the moment, and you will practice these modal verbs in sentences that matter to you, not in an abstract exercise. PBC also offers free language exchanges with native speakers, where you can practice English in real dialogue and hear how native speakers use these words.

The first class is free. You can try it and see how different it feels to learn a language by actually using it with people.

If you want to start practicing today, you can join a free exchange at pbclanguages.com and connect with a native English speaker. Speaking to a real person will cement these modal verbs in your memory far faster than any grammar rule ever will.