The high-frequency modal-plus-infinitive frames on this page show two learner-relevant surface patterns. In the first, the modal has an overt grammatical subject and agrees; in the second, the predicate stays in default masculine singular and a ל־ phrase can identify the relevant participant. Both put an infinitive immediately after the modal frame: אני צריך ללכת, אפשר לשלם, כדאי לך לנוח, אנחנו חייבים לחכות. The infinitive itself never agrees.
This contrast is not a complete taxonomy of Hebrew modality. In particular, צריך also has a separate subjectless impersonal frame, as in צריך להזמין, covered on its own page.
One surface skeleton, two kinds of modal
Inflecting modals take a grammatical subject and agree with it. צריך, חייב and יכול belong here: היא צריכה, הם חייבים, אנחנו יכולים.
Frozen modal frames stay in one form. אפשר, מותר, אסור and כדאי do not agree with a person inside this construction. When a person must be named, Hebrew normally puts that participant in a ל־ form: אפשר לי, מותר לה, אסור לנו, כדאי לך.
“Frozen” describes the frame, not necessarily the word everywhere in Hebrew. אפשר and adverbial כדאי are genuinely invariant, but מותר and אסור are also ordinary agreeing participles outside this construction: החנייה מותרת, הכניסה אסורה. Likewise, קשה agrees in העבודה קשה but stays masculine singular in modal קשה לי להסביר.
| Family | Participant | Modal | Infinitive | Complete frame |
|---|---|---|---|---|
| inflecting | אני | צריך | ללכת | אני צריך ללכת |
| inflecting | אנחנו | חייבים | לחכות | אנחנו חייבים לחכות |
| frozen | — | אפשר | לשלם | אפשר לשלם |
| frozen | לכם | מותר | להיכנס | מותר לכם להיכנס |
| frozen | לך | כדאי | לנוח | כדאי לך לנוח |
| frozen | לנו | אסור | לאחר | אסור לנו לאחר |
אני צריך ללכת, הרכבת האחרונה יוצאת בעוד רבע שעה.
aní tsaríkh lalékhet, harakévet ha'akharoná yotsét be'ód réva sha'á
I need to go; the last train leaves in fifteen minutes. (m. speaker; inflecting modal)
אנחנו חייבים לחכות לטכנאי עד שתיים.
anákhnu khayavím lekhakót latekhnái ad shtáyim
We have to wait for the technician until two. (inflecting modal)
אפשר לשלם באשראי או רק במזומן?
efshár leshalém be'ashrái o rak bimezumán?
Can one pay by card, or only in cash? (natural service question; frozen modal with no named person)
מותר לחנות פה אחרי שש בערב.
mutár lakhanót po akharéi shesh ba'érev
Parking is allowed here after six in the evening. (frozen modal, impersonal rule)
The subject-to-dative swap
The clearest way to see the contrast is to keep the participant and action constant while changing the modal. The meanings are not identical—must, can and would be wise contribute different force—but the same person still performs the infinitive's action.
| Participant and action | Inflecting modal: real subject | Frozen modal: ל־ participant |
|---|---|---|
| one man rests | אַתָּה צָרִיךְ לָנוּחַ atá tsaríkh lanúakh You need to rest. | כְּדַאי לְךָ לָנוּחַ kedái lekhá lanúakh You would be wise to rest. |
| one woman enters | אַתְּ יְכוֹלָה לְהִיכָּנֵס at yekholá lehikanés You can enter. | מוּתָר לָךְ לְהִיכָּנֵס mutár lakh lehikanés You are allowed to enter. |
| we return early | אֲנַחְנוּ חַיָּיבִים לַחֲזוֹר מוּקְדָּם anákhnu khayavím lakhazór mukdám We must return early. | כְּדַאי לָנוּ לַחֲזוֹר מוּקְדָּם kedái lánu lakhazór mukdám We would be wise to return early. |
English puts you in subject position in both “you need to rest” and “it is advisable for you to rest.” Hebrew makes the distinction visible: אתה צריך has a subject and agreement, while כדאי לך has frozen כדאי plus dative לך.
היא צריכה לנוח היום, היא כמעט לא ישנה בלילה.
hi tsrikhá lanúakh hayóm, hi kim'át lo yashná baláyla
She needs to rest today; she hardly slept last night. (inflecting modal agrees feminine singular)
כדאי לה לנוח היום ולא לענות למיילים.
kedái la lanúakh hayóm veló la'anót leméilim
She would be wise to rest today and not answer emails. (frozen modal plus ל־ experiencer)
הם חייבים לחזור לפני שסוגרים את השער.
hem khayavím lakhazór lifnéi shesogrím et hashá'ar
They have to return before the gate is closed. (inflecting plural modal)
The fuller classification, including borderline predicates, belongs on inflecting versus frozen modals. The complete forms of צריך are on צריך: need and must.
The ל־ phrase is a semantic participant, not the infinitive's object
In כדאי לך לנסוע, לך is not the object of “travel”: nobody travels “to you.” It is an experiencer or affected participant attached to the frozen predicate. Because the frozen word has no person agreement, the dative tells us who receives the advice, permission, prohibition or difficulty—and normally who is understood to perform the infinitive.
The same structure extends beyond the title's four modals. קשה לי להסביר means “it is difficult for me to explain.” The infinitive stays impersonal in form; לי identifies the person experiencing the difficulty.
כדאי לך לנסוע ברכבת, הכביש פקוק לגמרי.
kedái lekhá linsóa barakévet, hakvísh pakúk legamréi
You'd be better off taking the train; the road is completely jammed. (to one man)
אסור לנו לאחר שוב, המנהל כבר כועס.
asúr lánu le'akhér shuv, hamenahél kvar ko'és
We must not be late again; the manager is already angry. (frozen prohibition plus לנו)
קשה לי להסביר את זה בטלפון; אפשר להיפגש?
kashé li lehasbír et ze batélefon; efshár lehipagésh?
It's hard for me to explain this over the phone; can we meet? (frozen experiencer frame)
The dative forms themselves—לי, לך, לו, לה, לנו, לכם, לכן, להם, להן—are taught on ל־ with pronouns.
No extra linker before the infinitive
The modal is followed directly by the infinitive. Hebrew does not insert a separate equivalent of English to, because the infinitive's initial ל is already part of the word: צריך ללכת, מותר להיכנס, כדאי לנוח.
The apparent double ל in צריך ללכת is not a duplicated prefix. צריך ends in ך; ללכת itself begins with two written lameds because the infinitive prefix ל attaches to the weak verb whose stem also begins with ל in this form. Learn the infinitive as a word rather than counting letters.
אפשר לי להיכנס עכשיו או לחכות בחוץ?
efshár li lehikanés akhsháv o lekhakót bakhúts?
May I go in now, or should I wait outside? (frozen אפשר plus לי)
אתם צריכים למלא את הטופס ולחתום למטה.
atém tsrikhím lemalé et hatófes velakhtóm lemáta
You need to fill in the form and sign at the bottom. (to a group; inflecting modal)
Spelling the frozen forms
Three high-frequency items invite avoidable spacing errors:
- אי אפשר “impossible, cannot” is two words.
- כדאי “advisable, worth it” is one word.
- אסור “forbidden” is one word.
אי אפשר לשלם כאן במזומן.
i efshár leshalém kan bimezumán
It isn't possible to pay cash here.
Common Mistakes
1. Giving אפשר an English-style subject. The person belongs in a ל־ phrase.
❌ דנה אפשר לצאת מוקדם היום?
Incorrect—אפשר cannot take דנה as a subject. Put the participant in a ל־ phrase: אפשר לדנה…?
✅ אפשר לדנה לצאת מוקדם היום? יש לה תור לרופא.
efshár ledána latsét mukdám hayóm? yesh la tor larofé
Can Dana leave early today? She has a doctor's appointment.
2. Putting a pronoun subject before מותר. Permission uses מותר + dative.
❌ היא מותר לחנות פה
Incorrect—מותר does not agree with היא. Use מותר לה.
✅ מותר לה לחנות פה עד שמונה בערב.
mutár la lakhanót po ad shmóne ba'érev
She is allowed to park here until eight in the evening.
3. Adding a preposition before an infinitive that already starts with ל. The extra ל creates no grammatical form.
❌ מותר לי ללהיכנס עכשיו?
Incorrect—להיכנס is already the infinitive. Do not add another ל.
✅ מותר לי להיכנס עכשיו או שהחדר סגור?
mutár li lehikanés akhsháv o shehakhéder sagúr?
Am I allowed to go in now, or is the room closed?
4. Leaving the second action finite after an inflecting modal. The modal carries agreement; the action is an infinitive.
❌ אנחנו חייבים נחכה כאן
Incorrect—after חייבים, use the infinitive לחכות.
✅ אנחנו חייבים לחכות כאן עד שהרופא יתפנה.
anákhnu khayavím lekhakót kan ad sheharofé yitpané
We have to wait here until the doctor is free.
5. Joining אי אפשר into one word. This is an orthographic error, not a pronunciation difference.
❌ איאפשר להיכנס בלי קוד
Incorrect spelling—אי אפשר is always two words.
✅ אי אפשר להיכנס בלי הקוד שקיבלת בהודעה.
i efshár lehikanés bli hakod shekibálta bahoda'á
You can't enter without the code you received in the message. (to one man)
Key Takeaways
- Every modal frame on this page is followed directly by an infinitive.
- Inflecting modals take subjects and agree: היא צריכה, הם חייבים.
- Frozen modal frames stay fixed and use ל־ for a person: כדאי לך, מותר לה, אסור לנו; some of those words agree normally outside the frame.
- The dative identifies the semantic participant or experiencer; it is not the infinitive's object.
- Do not add a second ל before an infinitive.
- Spell אי אפשר as two words; כדאי and אסור as one word each.
Now practice Hebrew
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Start learning Hebrew →Related Topics
- Which Modals Inflect and Which Stay FrozenB1 — Distinguish Hebrew modals that agree with a nominative subject from impersonal frames that stay masculine singular and mark the affected person with ל־.
- צריך: Need and MustA1 — One word covers English's need, have to and should — and it is not a verb. צריך is an adjective, so it agrees with its subject (צריך, צריכה, צריכים, צריכות) and has no tense of its own. It takes either an infinitive or a plain noun, and it can also stand with no subject at all.
- אפשר and אי אפשר: Possible and ImpossibleA2 — Use invariant אפשר with an infinitive for possibility and polite requests, negate it with אי אפשר, and distinguish it from the verb אִפְשֵׁר.
- לי, לך, לו: ל־ InflectedA1 — The first inflected paradigm a learner needs, drilled cell by cell. לי marks possession (יש לי), a recipient (תן לי), the argument of a whole class of verbs (עזר לי) — and the experiencer in several everyday state constructions: קר לי, כואב לי, נמאס לי.