-t

The accusative suffix -t is the most frequent case marker in Hungarian. Its application depends on the ending of the word:

• Direct Attachment: If a word ends in a vowel, add -t directly. Note that final -a becomes -á and -e becomes -é (e.g., alma 'apple' → almát). Most other final vowels (including already long vowels like -í, -ó, -ú, -ő, -ű) remain unchanged when the -t is added (e.g., kocsi 'car' → kocsit). It also often attaches directly to words ending in a single consonant from this group: liquids, the nasals n and ny, and sibilants: -l, -r, -n, -ny, -j, -ly, -s, -sz, -z, -zs (e.g., sör 'beer' → sört, busz 'bus' → buszt). However, if the word ends in a consonant cluster (two or more consonants), a linking vowel is required even if the final consonant is in this list (e.g., vers 'poem' → verset, sors 'fate' → sorsot). Additionally, low-vowel stems override this direct attachment rule for these single consonants (e.g., ház 'house' → házat and víz 'water' → vizet, even though they end in z).
• Linking Vowels: A linking vowel is needed for words ending in most other consonants. Vowel harmony determines the choice: -ot or -at for back vowels (e.g., bot 'stick' → botot, while many back-vowel nouns take -at, e.g., hal 'fish' → halat), -et for unrounded front vowels (e.g., szék 'chair' → széket), and -öt for rounded front vowels (e.g., bőrönd 'suitcase' → bőröndöt). Note that adjectives often take different linking vowels than nouns, typically preferring -at/-et (e.g., pirosat 'red' instead of pirosot).
• Proper Nouns: Unlike in English, proper nouns (names of people, cities, countries) must also take the accusative suffix when they are the direct object (e.g., László 'László' → Lászlót, Budapest 'Budapest' → Budapestet, Magyarország 'Hungary' → Magyarországot).
• Pronouns: Personal pronouns have irregular accusative forms (e.g., én 'I' → engem, te 'you' → téged). Demonstrative pronouns in the singular always take the suffix directly (ez 'this' → ezt, az 'that' → azt), while their plural forms use linking vowels (ezek 'these' → ezeket, azok 'those' → azokat).
• Stem Changes: Some words are 'low-vowel stems' and use -at/-et instead of the standard linking vowels (e.g., ház 'house' → házat instead of házot). For example, könyv 'book' is an exception because its rounded vowel ö would normally dictate -öt, but as a low-vowel stem, it takes -et (könyvet). Others may shorten their vowels (víz 'water' → vizet), drop a vowel (eper 'strawberry' → epret), or add a 'v' (ló 'horse' → lovat, kő 'stone' → követ).
• Last in Line: The accusative suffix is always the absolute last suffix attached to a noun, coming after plural and possessive markers (e.g., barát-om-at 'my friend').
• Possessive Linking Vowel Shift: When a noun has a possessive suffix, its accusative linking vowel is restricted to -a- or -e-. Back-vowel nouns shift to -at instead of the standard -ot (e.g., virágot 'flower' vs. virágomat 'my flower'), and front rounded vowels shift from -öt to -et (e.g., bőröndöt 'suitcase' vs. bőröndömet 'my suitcase').
• Plural Shortcut: If the accusative requires a linking vowel, it almost always matches the plural linking vowel (e.g., if the plural is házak 'houses', the accusative is házat), saving you from memorizing exceptions twice. Note that many words take a linking vowel in the plural but attach -t directly in the accusative (e.g., buszok 'buses' but buszt 'bus'). Additionally, if a noun is already in the plural (ending in -k), the accusative linking vowel is always reduced to -a- or -e- (never -ot or -öt). Therefore, the plural accusative ending is always -kat or -ket (e.g., könyvek 'books' → könyveket, lányok 'girls' → lányokat).

Important Nuance: It is a standard grammatical option to drop the -t suffix after 1st and 2nd person singular possessive suffixes (e.g., Kérem a könyvem 'I want my book' instead of könyvemet).

Important Warning: Attributive Adjectives (adjectives directly modifying a noun) do not take the accusative case in Hungarian (e.g., a piros almát 'the red apple', not a pirosat almát). Adjectives only take the -t suffix when acting as standalone nouns or pronouns.