-ni

The infinitive is a versatile tool in Hungarian. Here is how to form and use it:

1. Formation:

• Standard: Add -ni to stems ending in a vowel or a single consonant (e.g., vár → várni).
• Linking Vowels: If a stem ends in two consonants or a long vowel + 't', use -ani/-eni based on vowel harmony (-a- for back vowels and -e- for front vowels) (e.g., mond → mondani, segít → segíteni). Note that -ít is a very common verb-forming suffix, so any verb ending in it will follow this rule (e.g., tanít → tanítani, fordít → fordítani).
• Exceptions: Some verbs omit a normally required linking vowel (e.g., állni to stand, szállni to fly, varrni to sew, forrni to boil, and látni to see, which has a long vowel + 't' but is just látni). Others add an unexpected linking vowel despite ending in a single consonant (e.g., védeni to protect, edzeni to train).
• -Ik Verbs: For many -ik verbs, you remove the -ik ending and then apply the standard linking vowel rules to the remaining stem (e.g., lakik → lakni, but ugrik → ugrani because ugr- ends in two consonants). However, true 'sz-stem' verbs undergo a stem change (e.g., alszik → aludni, fekszik → feküdni). Note that regular verbs that simply end in -szik follow the standard rule (e.g., úszik → úszni, mászik → mászni).

2. Irregular Stems:
Several common verbs have special stems for the infinitive:

• van (is) and lesz (will be/become) → lenni
• megy (goes) → menni
• jön (comes) → jönni
• eszik (eats) → enni
• iszik (drinks) → inni
• tesz, vesz, visz, hisz → tenni, venni, vinni, hinni

3. Usage:

• With Modals: Used with verbs like akar (want) and tud (can).
• Necessity and Permission: Used with impersonal words like kell (must/need), lehet (it is possible/allowed), szabad (it is allowed/permitted), and tilos (it is forbidden). Note that kell + bare infinitive is for impersonal statements (e.g., Enni kell - One must eat). For specific people, Hungarian uses inflected infinitives. To form these, you add possessive-style endings to the infinitive stem. The -i is dropped for the 1st and 2nd persons (both singular and plural) but kept for the 3rd person (singular and plural). The endings are: -nom/-nem/-nöm, -nod/-ned/-nöd, -nia/-nie, -nunk/-nünk, -notok/-netek/-nötök, -niuk/-niük (e.g., menni → mennem kell - I must go, mennie kell - he/she must go).
• Future Tense: The infinitive is required with the auxiliary verb fog to express future actions (e.g., Dolgozni fogok - I will work).
• Verbal Prefixes: When an infinitive with a verbal prefix is used with a conjugated auxiliary verb (like akar, tud, or fog), the prefix splits from the infinitive and jumps in front of the conjugated verb (e.g., megnézni + akarom = Meg akarom nézni - I want to watch it).
• As Subject/Object: The infinitive is frequently used as the subject of a sentence to express general statements (e.g., Úszni jó - Swimming is good / It is good to swim, Tanulni jó - To study is good).
• Purpose: Often used after verbs of motion to show intent (e.g., Elmegyek aludni - I am going [in order] to sleep).