ez / az

Hungarian demonstratives serve two main roles: as pronouns (standing alone) and as determiners (pointing to a noun). For example: Ezt kérem (I want this [pronoun]) vs. Ezt a könyvet kérem (I want this book [determiner]).

1. The 'Double' Marker Rule
When ez or az points to a specific noun, you must follow it with the definite article (a or az).
Example: Ez a ház (This house).

2. Case Agreement
The demonstrative must match the noun's case. If the noun has a suffix, the demonstrative must have a suffix representing the same case. This is called demonstrative agreement. For example: ebben a házban (in this house) or azt a könyvet (that book).

3. Adding Suffixes
When adding a case suffix that begins with a consonant to the singular ez or az, the final -z changes to match that consonant:

• ez + -ben = ebben
• az + -nak = annak

When adding a suffix that begins with a vowel, the -z generally remains unchanged (e.g., ez + -ért = ezért; or with the superessive suffix, ez + -en = ezen, az + -on = azon).

Note: This assimilation only happens with the singular forms. Plural forms (ezek, azok) take suffixes like regular nouns without this assimilation (e.g., ezekben, not ebbekben). Also, remember vowel harmony: ez always takes front-vowel suffixes, and az always takes back-vowel suffixes.

Exceptions and Special Cases:

• With -val/-vel, both azzal/ezzel and avval/evvel are correct. While azzal/ezzel is the preferred standard in formal and written contexts, avval/evvel is slightly more colloquial.
• With the translative suffix -vá/-vé, the suffix's v assimilates to the demonstrative's z, resulting only in ezzé and azzá (forms like evvé/avvá are incorrect).
• With the accusative -t, no change occurs: ezt, azt.
• With the terminative suffix -ig (which starts with a vowel), the z changes to a double dd: eddig, addig.

4. Postposition Agreement
How demonstratives work with postpositions depends on how they are used:

• When pointing to a noun (determiner): For postpositions taking the nominative case (like előtt, mögött), the postposition is repeated after the demonstrative. If the postposition begins with a vowel, the ez/az remains unchanged (e.g., Ez előtt a ház előtt). If the postposition begins with a consonant, the -z drops, leaving just e or a (e.g., A mögött a ház mögött).
• Established adverbial uses: The demonstrative can merge with the postposition into a single compound word. Independent reference to a concrete object does not by itself require joining the words. If the postposition starts with a consonant, the -z drops (e.g., ez + mellett = emellett). If it starts with a vowel, the -z remains (e.g., ez + alatt = ezalatt).
• Postpositions requiring a case suffix (like szemben, which takes -val/-vel): The demonstrative takes the required case suffix, and the postposition is not repeated.
  Example: Ezzel a házzal szemben (Opposite this house)

Orthography Warning: When writing the demonstrative and postposition as a single word (e.g., ezelőtt, azután, ezalatt), they can have established temporal or other adverbial meanings, such as ezelőtt (formerly). When pointing to a noun, they must be written as two separate words (e.g., ez előtt a ház előtt).

5. Plural Forms
If the noun is plural, the demonstrative must also be plural. If the noun is both plural and has a case suffix, the demonstrative must agree in both number and case simultaneously:

• Ezek a könyvek (These books)
• Azok a házak (Those houses)
• Ezekben a könyvekben (In these books)

Note: When adding the -val/-vel suffix to plural demonstratives, the v assimilates to the k, resulting in ezekkel and azokkal.