Modal-Like Expressions

English has a parallel system of modality that doesn’t use modal verbs at all. Instead, it uses adjective + to-infinitive patterns built on the verb be: be liable to, be apt to, be prone to, be inclined to, be likely to, be bound to, be due to, be supposed to, be meant to. Each one expresses a shade of probability, tendency, obligation, or expectation that the modal verbs might, will, should, and must don’t quite capture.

These expressions are everywhere in American English at C1 register — in journalism, legal writing, technical analysis, weather forecasting, business communication, and even casual conversation. He’s bound to find out eventually. The flight’s due to leave at 6. You’re not supposed to park there. Master them and you gain a second modal system that runs in parallel with the first.

This lesson takes them one by one, contrasts the closest pairs (likely vs apt vs liable vs prone), and unpacks the C1-level subtleties of supposed to vs meant to.

The full inventory at a glance

Each one occupies a slot the modal verbs can’t reach precisely.

Be likely to — probable

The plain probability marker. Closest to will probably.

• It’s likely to rain this afternoon.
• The Fed is likely to raise rates again in September.
• Most graduates are likely to find work within six months.
• She’s likely to be elected.

Negation: unlikely to do.

• Voters are unlikely to forget this scandal anytime soon.
• He’s unlikely to apologize.

In contexts where probability needs a number-feel — weather, business forecasting, statistical reporting — likely to is the default.

Be apt to — tend to (with mild negative connotation)

Apt to sits between probability and habit. It describes a tendency — something the subject does or that happens often, usually with a slightly negative or risky flavor.

• He’s apt to lose his temper when he’s tired.
• The old printer is apt to jam halfway through a long job.
• Tourists are apt to underestimate how cold it gets at night.
• Forecasts at this distance out are apt to be wrong.

Compare with likely to (more neutral, more probability-focused):

• He’s likely to lose his temper. (statistical-feeling — probable on a given occasion)
• He’s apt to lose his temper. (it’s a tendency, a known feature of him)

Apt to is somewhat formal/written; in casual speech, tends to often replaces it.

Be liable to — likely to (with negative consequence) / legally responsible

Liable to has two related meanings.

Meaning 1: likely to suffer a negative outcome.

• If you don’t wear sunscreen, you’re liable to get a burn.
• Cars left here overnight are liable to be towed.
• He’s liable to say something he’ll regret.

The construction implies the consequence is unpleasant.

Meaning 2: legally responsible.

• The company is liable to the plaintiff for damages.
• Each partner is personally liable for the firm’s debts.
• You may be held liable if a guest is injured on the property.

In legal-flavored writing, liable slides between “probable bad outcome” and “legally responsible” — the same word does both jobs.

Be prone to — tend toward (negative predisposition)

Prone to describes a predisposition — a structural tendency, often used in medical, behavioral, or technical contexts.

• He’s prone to migraines.
• Older systems are prone to corruption when the power flickers.
• Children are prone to ear infections at this age.
• Politicians are prone to overpromising during campaign season.

Pattern: prone to + noun (most common) or prone to + V-ing (less common). The thing the subject is prone to is almost always undesirable.

Be inclined to — lean toward

Inclined to describes a disposition or leaning — usually toward an opinion or action, often with a hedge.

• I’m inclined to agree with you.
• The committee is inclined to approve the proposal, pending review.
• She’s inclined to let it slide this time.
• I’d be inclined to take the second offer if I were you.

This is one of the most useful C1 diplomatic phrases. I’m inclined to think… signals an opinion held tentatively — common in academic and professional discourse where outright assertion sounds combative.

Be bound to — almost certain to

Bound to expresses near-certainty, often with a sense of inevitability. Roughly equivalent to almost certainly will.

• He’s bound to find out eventually.
• With that much pressure, something is bound to give.
• The kids are bound to be hungry by the time we get home.
• You’re bound to make mistakes when you’re learning a new system.

Bound to often carries a tone of resigned acceptance — “this is going to happen, there’s no fighting it.” It’s a workhorse of AmE conversation.

Be due to — scheduled to / expected to

Due to describes a scheduled or expected event.

• The flight is due to land at 5:47.
• She’s due to give birth in March.
• The report is due to come out next week.
• Construction is due to start in the fall.

Don’t confuse with due to meaning because of (a different construction):

• The delay was due to mechanical issues. (= because of — different sense)
• The flight is due to depart at 6. (= scheduled to)

The two constructions are different beneath the surface: in be due to + V (schedule), due is an adjective taking an infinitive complement; in due to + NP (cause), due to functions as a complex preposition. They look identical only because they share the words due to; the syntactic category and the dependent type differ.

Be supposed to — expected to (by rule, plan, reputation)

The workhorse phrase. Three main uses:

1. Rule / regulation

• You’re not supposed to park here after 6 p.m.
• Students are supposed to wear name tags.
• We’re supposed to keep the back door locked.

2. Plan / expectation

• I’m supposed to meet her at noon.
• The package was supposed to arrive yesterday.
• He’s supposed to be in charge of the project.

3. Reputation / reported information

• This restaurant is supposed to be excellent.
• The new Bond movie is supposed to be terrible.
• He’s supposed to be the best surgeon in the state.

The third use is hearsay — “people say.” Russian speakers rarely produce this use because Russian uses a different construction (говорят, что…).

Past form: was/were supposed to

The past form often implies the expectation was not met.

• I was supposed to call her yesterday. (implication: I didn’t)
• We were supposed to leave at 8. (implication: we didn’t)
• The package was supposed to arrive by Tuesday. (implication: it didn’t)

This unspoken “but didn’t” is a distinctive feature. Was supposed to is almost always disappointment.

Be meant to — intended to / supposed to

Meant to overlaps with supposed to but has a slightly different flavor — emphasizing intention more than rule.

• This software is meant to streamline scheduling. (intended function)
• I’m meant to be there at 9. (close to supposed to be, slightly more “by plan”)
• That comment wasn’t meant to be taken seriously.
• The exhibition is meant to challenge the viewer.

Past form: was/were meant to — like was supposed to, often implies the intention wasn’t realized.

• The trip was meant to be relaxing. (but wasn’t)
• He was meant to lead the team, but the role went to someone else.

Stacking and combining

Real prose stacks these expressions for finer shading:

• He’s liable to be inclined to reject the offer, given his history. (likely + disposed)
• The vote is due to take place Thursday, and the outcome is bound to be close. (scheduled + nearly certain)
• Patients prone to migraines are more likely to report sensitivity to light. (predisposition + probability)

Negation patterns

Disinclined to is a useful formal hedge: The board is disinclined to approve the merger without more data.

AmE notes

“Supposed to” is universal AmE. It appears in everything from elementary-school rules (You’re not supposed to run in the hall) to corporate communication (We’re supposed to file this by EOD). Russian speakers underuse it dramatically because Russian uses должен or impersonal constructions for the same semantic territory.

“Bound to” carries Southern AmE flavor in some contexts. I’m bound to do it sounds especially natural in Southern American speech — though it’s also used everywhere else. In Northern AmE business writing, bound to is fully neutral.

“Apt to” is more BrE-flavored. AmE speakers reach for tends to or is likely to in casual speech where BrE might use apt to. In AmE writing, apt to is still common and unmarked.

“Meant to” with hearsay reading is more BrE. The new restaurant is meant to be amazing sounds slightly British to American ears; AmE speakers usually say supposed to be amazing. Both work in AmE writing.

“Due to” + verb is gaining ground in AmE business communication. The project is due to wrap up next month is corporate-standard AmE.

Pronunciation notes

• Supposed to compresses heavily: /səˈpoʊstə/ — the d and the to merge. Supposeta is the rapid-speech pronunciation. Same with used to → /juːstə/.
• Meant to → /ˈmɛn(t)tə/ — the second t often elides.
• Bound to → /ˈbaʊn(d)tə/ — d often dropped.
• Liable to → /ˈlaɪəbəl tə/ — three syllables, with reduced final.
• Likely to → /ˈlaɪkli tə/ — straightforward.
• Apt to → /ˈæp(t) tə/ — t often elides into the next t.
• Due to → /ˈduː tə/ or /ˈdjuː tə/ (the y glide is more BrE; AmE drops it).
• Stress in these constructions falls on the modal adjective, not the to: He’s LIKEly to be late; She’s BOUND to find out.

Common Russian-speaker mistakes

1. Underusing supposed to: defaulting to must or should where AmE would use supposed to. I must call her at 9 → I’m supposed to call her at 9. The latter is the natural AmE expression of a planned obligation.
2. Missing the “but didn’t” implication of was supposed to: producing I was supposed to call her yesterday and meaning “and I did, on time.” In AmE, the past form almost always implies the obligation wasn’t met. Use plain past for completed plans: I called her yesterday at 9, as planned.
3. Confusing due to (cause) with due to (schedule): The flight is due to mechanical problems → The flight is delayed due to mechanical problems. Due to + noun phrase is causal; due to + verb is scheduled.
4. Using prone to for positive predispositions: She’s prone to success (sounds wrong) → She’s likely to succeed or She has a strong shot at succeeding. Prone to is for negative tendencies.
5. Calquing Russian “склонен думать”: I am tend to think → I’m inclined to think or I tend to think. Inclined to is the formal equivalent.
6. Using bound to with a hedging tone: bound to expresses near-certainty. Don’t use it for a 50/50: He’s bound to come maybe → He might come or He’s likely to come.
7. Mixing meant to and meant for: This software is meant for streamline scheduling → meant to streamline (verb) or meant for streamlining (gerund) / meant for finance teams (noun). Meant to takes a verb; meant for takes a noun.
8. Translating Russian “должен был” uniformly as must have done: I was supposed to call her (didn’t) vs I had to call her (did) vs I must have called her (deduce I did) — Russian “должен был” collapses all three.

Summary

• Modal-like expressions = be + adjective/participle + to-infinitive; parallel modal system covering probability, tendency, schedule, expectation.
• Likely to (probable), apt to (characteristic tendency), liable to (probable + negative; legal), prone to (structural predisposition + negative), inclined to (leaning), bound to (near-certain), due to (scheduled), supposed to (rule/plan/hearsay), meant to (intended).
• Was/were supposed to usually implies the expectation wasn’t met.
• Supposed to is the AmE workhorse for planned/expected/by-rule modality — Russian speakers underuse it.
• Inclined to is a key C1 diplomatic hedge.
• Be due to + verb means scheduled (due as adjective + infinitive); due to + noun means caused by (due to as complex preposition + NP) — same surface words, different syntactic categories.

Next lesson: Modality in academic and formal writing — modal stacking, hedging, epistemic vs deontic in scholarly and business prose.