Historical Infinitive Syntax

In modern Hungarian, inflected infinitives are strictly limited to impersonal, evaluative, or modal predicates (like kell or lehet). Common modern examples include Haza kell mennem (I have to go home), Itt lehet aludnotok (You guys can sleep here), and Nincs mit tennünk (There is nothing for us to do). However, in Old and Middle Hungarian, they could be used as complements to standard, subject-agreeing matrix verbs (e.g., akar, kezd, lát).

Morphological Rules:

• The suffixes attach to the verb stem via the infinitive marker -ni. Verbs ending in two consonants, a long vowel followed by -t (e.g., fűt, tanít, bocsát), or specific exceptions like véd and edz require a linking vowel before the infinitive marker (e.g., segít → segíteni → segítenem). However, lát is a notable exception to the long vowel + -t rule and attaches -ni directly (látni). Similarly, verbs ending in -ll or -rr (e.g., áll, száll, varr, forr) are exceptions and attach the -ni marker directly without a linking vowel (e.g., állni → állnom).
• Irregular verbs build these forms on their specific infinitive stems, not the present tense dictionary stem (e.g., megy → menni → mennem).
• Crucially, the -i of the infinitive marker is dropped before 1st and 2nd person suffixes (e.g., mennem, látnod).
• The -i is retained in the 3rd person (e.g., mennie, látniuk).
• The 1st/2nd person singular and 2nd person plural are subject to Three-Way Suffix Harmony (e.g., 1st person singular is -nom / -nem / -nöm). The 3rd person singular (-nia/-nie), 1st person plural (-nunk/-nünk), and 3rd person plural (-niuk/-niük) only have two-way Vowel Harmony.

Full Paradigm Example (látni):

• 1st sg: látnom
• 2nd sg: látnod
• 3rd sg: látnia
• 1st pl: látnunk
• 2nd pl: látnotok
• 3rd pl: látniuk

Dative Subjects, Prefix Splitting & Negation:
The logical subject of an inflected infinitive takes the Dative Case (-nak/-nek or dative pronouns like nekem, neked, neki, nekik). For example: Jánosnak mennie kell (János has to go) or Nekem látnom kell (I have to see). Because the infinitive is inflected for person, the dative pronoun is usually dropped unless used for emphasis or contrast. Crucially, when a plural dative subject is explicitly stated (e.g., a gyerekeknek), the inflected infinitive typically takes the 3rd person singular ending to avoid redundancy (e.g., A gyerekeknek haza kell mennie), similar to possessive noun phrases. Furthermore, when an inflected infinitive with a verbal prefix is used with a modal like kell, the prefix detaches and jumps in front of the modal (e.g., el kell mennem), following the rules of Prefix Climbing with Kell. When negating these constructions, the negative word nem is placed before the modal or impersonal verb, not the infinitive (e.g., Nem kell mennem = I don't have to go).

Register & Possessive Connection:
The Old Hungarian syntax of using these with standard matrix verbs is highly archaic and obsolete, encountered exclusively in historical texts, old hymns, or highly stylized literary texts. However, the morphological forms themselves are very much alive and used daily with impersonal, evaluative, or modal verbs. It is a common misconception that these are 'verb endings'; authoritative linguistic sources emphasize that they are morphologically identical to Type II possessive suffixes, reflecting the historically nominal nature of the Hungarian infinitive. Comparing noun possessive suffixes to inflected infinitives makes this clear: a kutyám (my dog) vs. látnom (my seeing); a kutyád (your dog) vs. látnod (your seeing). Recognizing this connection significantly reduces the memorization burden.