Inflected Infinitives

The inflected infinitive is a distinctive feature of Hungarian grammar used to specify the subject of an action in impersonal constructions.

1. General vs. Specific:
The plain infinitive (-ni) is used for general statements (e.g., Kell aludni - One must sleep). The inflected infinitive is used when the action refers to a specific person (e.g., Aludnom kell - I must sleep). Note that when the specific person is explicitly marked with a dative noun or pronoun, the personal suffix on the infinitive becomes grammatically optional. Therefore, both Nekem kell aludni and Nekem aludnom kell are fully correct and accepted in standard Hungarian.

2. When to use it:
It is most commonly used with expressions like:

• kell (must/need)
• muszáj (must/compulsory)
• lehet (possible/may)
• szabad (allowed)
• tilos (forbidden)
• illik (proper/fitting)
• sikerül (to succeed)

3. How to form it:
To form the inflected infinitive, drop the full -ni ending from the verb and add the personal infinitive endings (e.g., olvasni -> olvas- + -nom = olvasnom). Note that irregular infinitives like lenni (to be) and enni (to eat) follow the exact same rule: drop the -ni to get the stem (e.g., len-) and add the endings (e.g., lennem). The endings follow vowel harmony. However, some verbs with front vowels are historical exceptions and take back-vowel suffixes, such as inni (to drink, e.g., innom), írni (to write, e.g., írnom), hívni (to call, e.g., hívnom), sírni (to cry, e.g., sírnom), and nyitni (to open, e.g., nyitnom). The 1st person singular, 2nd person singular, and 2nd person plural follow three-way harmony (o/e/ö). The 1st person plural, 3rd person singular, and 3rd person plural use two-way harmony (a/e and u/ü).

• Back: -nom, -nod, -nia, -nunk, -notok, -niuk
• Front: -nem, -ned, -nie, -nünk, -netek, -niük
• Front Rounded: -nöm, -nöd, -nie, -nünk, -nötök, -niük

4. The Subject:
If the subject is a specific noun, it must be in the dative case (-nak/-nek) (e.g., Péternek kell mennie). However, personal pronouns in the dative (nekem, neked) are usually omitted unless you need emphasis, as the suffix already indicates the person.

5. Verbal Prefixes:
When using a verb with a verbal prefix (igekötő), the prefix splits from the verb and moves before trigger words like kell, szabad, lehet, and muszáj in affirmative sentences. The formula is: Prefix + Trigger Word + Infinitive (e.g., El kell mennem - I must go away). Note that tilos does not split the prefix (e.g., Tilos bemennem). Additionally, in negative sentences, questions, or sentences with a focused element, the prefix does not split and remains attached to the infinitive (e.g., Nem kell elmennem - I don't have to go away; Hova kell elmenned? - Where must you go?).