Modals
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The three modals of possibility: how English talks about the uncertain — and asks for permission politely.
All three express possibility — something is conceivable but not certain. "May" additionally handles formal permission ("May I…?"), and "could" is the polite choice for requests ("Could you…?").
Updated: July 2026
B1 · Modals · 9 min
A structured ten-slide lesson for B1 learners. Hear the three modals in context, meet the certainty scale with a tutor, then practise possibility, permission, and polite requests across six interactive drills before a final five-question quiz. The whole arc takes about nine minutes and nothing requires a signup.
Might, could, and may are the English tools for everything that sits between "definitely yes" and "definitely no". When you say "The delivery might be late", you are not making a claim about the future — you are flagging an open possibility. The delivery may arrive on time, or it may not; you are deliberately not committing. That refusal to commit is the core job of all three verbs, and they do it for the present and the future alike: "She might be in a meeting" (now) and "It could rain tomorrow" (later) follow exactly the same pattern. Because German funnels all of this into "könnte" or "vielleicht", the three English verbs can look like redundant copies of each other at first. They are not quite: in the possibility sense, might, could, and may are largely interchangeable, but "may" carries the extra job of formal permission, and "could" doubles as the standard verb for polite requests. Once you can keep the three jobs apart — speculating, permitting, requesting — you have already understood the hardest part of this lesson.
The mechanics are pleasantly simple as long as you respect three prohibitions. First: might, could, and may are always followed by the base form of the verb — "She might come", never "She might to come" or "She might comes". Second: the modals themselves never change; there is no "mights", no "mayed", no "coulding". Third: questions and negatives work without "do", because the modal itself acts as the auxiliary. The negatives are "might not" (rarely contracted to "mightn't"), "may not" (with no common contraction), and "could not / couldn't". Watch that last one: in the possibility sense, "couldn't" is not simply the opposite of "could". "The delivery could be late" means lateness is possible. "The delivery couldn't be late" means lateness is impossible — a far stronger claim. If you want to say "maybe not", you need "might not" or "may not": "The delivery might not arrive today." This asymmetry is one of the few genuine traps in the form system of these three verbs, and it is worth drilling deliberately once.
Picture a scale from zero to one hundred percent. At the far right sits "will": "The delivery will arrive tomorrow" is a firm prediction. At the far left sits "won't": ruled out. Might, could, and may live together in the middle — the maybe zone. Many coursebooks try to rank the three finely, for instance treating "may" as slightly more likely than "might". In real usage, though, the differences in the possibility sense are small and vary by speaker and context; the register differences are more reliable: "may" sounds more formal and more written, while "might" and "could" dominate everyday speech. More important than fine-ranking is the distance to the neighbours: "probably" ("She'll probably join") sits clearly above the maybe zone, and "probably not" clearly below it. Someone who says "The client might sign this week" in a meeting is promising nothing — and that is often precisely the point. The scale works in questions too: "Could this affect the budget?" asks about a possibility, not an ability. Only "may" is unusual in possibility questions; native speakers switch to "might" or "could" there.
Beyond possibility, these verbs have a second major job: permission and requests. Here the key variable is register — how formal you need to be. When you ask permission for yourself, the three-step ladder applies: "May I leave early?" is formal and respectful, "Could I leave early?" is polite and neutral, and "Can I leave early?" is informal and completely normal among colleagues. When you ask someone else to do something, the route is "Could you…?" or "Can you…?": "Could you send the report by five?" Importantly, "May you…?" does not work as a request in modern English — "may" is reserved for your own permission. One subtlety that regularly surprises learners: "may not" can mean two entirely different things. "You may not leave yet" is a formal refusal — permission denied. "She may not come tonight" is pure speculation — maybe she will not come. Context decides. When in doubt, "Could I…?" for yourself and "Could you…?" for others will carry you through almost every situation: polite enough for your boss, relaxed enough for your team.
The most common mistake German-speaking learners make with this topic has a clear origin: in German, "kann" covers both ability and possibility. "Es kann sein, dass die Lieferung zu spät kommt" is perfectly good German, and the word-for-word translation suggests itself: "It can be late." This is exactly where English draws a sharp line. "Can" describes abilities ("She can speak French") and general, recurring possibilities ("Winters here can be brutal" — winters in general). For the concrete, one-off possibility — this one delivery, this one afternoon — English demands might, could, or may: "The delivery might be late." A second branch of the same trap concerns permission: because German "kann ich…?" fits everywhere, many learners reach for "Can I…?" even in formal situations — grammatically fine, but a touch too casual in a job interview or with clients. There, "May I…?" or "Could I…?" is the better choice. A quick self-test helps: if you could add "vielleicht" to your German sentence, English wants might, could, or may — not can.
In business English, these three verbs are far more than grammar — they are risk language. A status update made entirely of confident statements looks either naive or reckless, because projects are rarely certain. Professionals therefore grade their claims: "The delivery might be delayed by a week", "This could affect the Q3 timeline", "We may need additional budget for testing". The technique is called hedging: you name a risk without declaring it a fact — and without nailing yourself to a promise. The pattern is just as pervasive in negotiations: "We could offer a discount if you commit to two years" keeps an offer floating that "We will offer…" would already make binding. And in forecasts, "Sales may improve in the second half" signals a grounded expectation without a guarantee. The difference from "will" is not a matter of style; it carries real accountability: writing "will" makes a promise, writing "might" issues a warning. For your next English meeting, one simple rule of thumb is enough: any statement about the future you would not bet on gets a might, could, or may.
In the possibility sense they are largely interchangeable: "The delivery might / could / may be late" means the same thing three times over — possible, but not certain. The real differences lie in their extra jobs and register: "may" is more formal and additionally handles official permission ("May I…?"), "could" is the default verb for polite requests ("Could you…?"), and "might" is the most neutral pure-possibility verb in everyday speech.
Because English "can" describes general possibilities and abilities, not a concrete possibility on one specific occasion. "Deliveries can be late" — deliveries in general are sometimes late — is fine. But for this one delivery tomorrow you need might, could, or may: "The delivery might be late." The trap comes from German, where "kann" does both jobs. Rule of thumb: if "vielleicht" fits in the German sentence, English wants might, not can.
In the possibility sense, surprisingly, no. "The delivery could be late" means lateness is possible. But "The delivery couldn't be late" does not mean "maybe not" — it means lateness is impossible, a much stronger claim. If you mean "maybe not", you need "might not" or "may not": "The delivery might not arrive today." This asymmetry only applies to the possibility meaning; for ability, "couldn't" is the ordinary opposite ("I couldn't swim as a child").
Broadly yes — the possibility meaning works identically on both sides of the Atlantic. The most noticeable difference is permission: in everyday American English, "Can I…?" is common even in fairly formal situations, while British English reaches for "May I…?" more often in permission questions. In both varieties "May I…?" counts as the most polite form, and European exams follow the British standard. If you are studying for a certificate, the ladder may > could > can keeps you on the safe side.
Before this, you should be solid on *can-cant* (A1) — ability and informal permission are the foundation this lesson builds on. The sister lesson *must-have-to-should* (B1) covers the other half of the B1 modals: obligation and advice instead of possibility. After this, *modals-deduction-present* (B1) is the natural next step: there you learn to draw logical conclusions with must, might, and can't ("She must be in a meeting") — the same verbs, a new job.
Historically, "might" was the past-tense form of "may", just as "could" was the past tense of "can". In modern English that time relationship has largely dissolved: "She might come tomorrow" is not past — it is present or future. What survived from the old past form is distance, and distance reads as politeness and caution in English. That is why "Could I ask a question?" sounds softer than "Can I ask a question?". The same pattern shows up in "will" and "would": the old past form has become the polite form.
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