-k

In Hungarian, plurality is marked by the suffix -k. Here are the rules for attaching it:

1. Vowel-ending stems:
For most nouns ending in a vowel, add -k directly.
• If the word ends in -a or -e, these vowels must lengthen to -á- and -é- (e.g., alma (apple) → almák).
• For nouns, most other vowels (ó, ő, i, etc.) do not change (e.g., autó (car) → autók). However, some nouns are irregular and add a 'v' (e.g., ló (horse) → lovak). For regular adjectives ending in -ó or -ő, add -k directly (e.g., jó (good) → jók, olcsó (cheap) → olcsók). However, for participles (adjectives derived from verbs), a linking vowel is optional (e.g., látható (visible) → láthatók or láthatóak).
• While many adjectives ending in -ú, -ű, or -i require a linking vowel (e.g., hosszú (long) → hosszúak, pesti (from Pest) → pestiek), there are exceptions that take -k directly, such as kicsi (small) → kicsik. Note that some words like sűrű (dense) can take either form (sűrűk or sűrűek).

2. Consonant-ending stems (Nouns):
A linking vowel is required for nouns based on vowel harmony:
• Back vowels: Use -ok (e.g., asztal (table) → asztalok).
• Front vowels (unrounded): Use -ek (e.g., ember (person) → emberek).
• Front vowels (rounded): Use -ök (e.g., sör (beer) → sörök). Note: Some stems drop a vowel when adding the suffix (e.g., tükör (mirror) → tükrök), and there are vowel-shortening stems where a long vowel becomes short in the plural (e.g., víz (water) → vizek, madár (bird) → madarak).

3. The 'Low-Vowel' Exception and Adjectives:
Some common nouns use 'low' linking vowels. For back-vowel words, this means using -ak instead of -ok (e.g., ház (house) → házak). For front-rounded words, this means using -ek instead of the standard -ök (e.g., fül (ear) → fülek). Importantly, adjectives ending in consonants almost always use these low linking vowels (-ak/-ek) instead of the standard noun ones (e.g., piros (red) → pirosak). However, there are common exceptions that take standard noun linking vowels (-ok/-ök). These include ethnonyms/nationalities (e.g., görög (Greek) → görögök, török (Turkish) → törökök), privative adjectives ending in -atlan/-etlen or -talan/-telen (e.g., boldogtalan (unhappy) → boldogtalanok), and some individual adjectives like nagy (big) → nagyok, gazdag (rich) → gazdagok, and boldog (happy) → boldogok.

4. Numbers and Quantifiers:
In Hungarian, you must use the singular form of a noun after numbers and quantifiers like sok (many) or kevés (few). You say három kutya (three dogs), never három kutyák.

5. Possession Conflict:
The plural -k is not used if the noun already has a possessive suffix. Instead, a special plural marker -i is used before the possessive ending (e.g., kutyáim = my dogs).

6. Adjective and Demonstrative Agreement:
Plurality isn't just for nouns. When an adjective is used as a predicate (e.g., 'The dogs are big'), it must also take the plural suffix to agree with the noun: A kutyák nagyok. However, attributive adjectives placed directly before a noun never take the plural suffix (e.g., a nagy kutyák = the big dogs, not a nagyok kutyák). Unlike attributive adjectives, demonstrative pronouns (ez / az) must agree with the plural noun (e.g., ezek az almák = these apples).

7. Suffix Ordering:
In Hungarian, suffixes stack onto each other. The plural -k always comes before case suffixes. For example, könyvek (books) + -ben (in) becomes könyvekben (in books).