ki

In Hungarian, ki is the primary way to ask about the identity of a person. Here are the key rules for its usage:

• Primarily for Humans: Use ki for people (and occasionally for specific, beloved pets). For animals or objects, use mi (what). For an emphatic version, you may hear kicsoda. Note that unlike ki, kicsoda takes back-vowel suffixes (e.g., kicsodát, kicsodának).
• Plurality: If you expect the answer to be more than one person, you must use the plural form kik. For example, 'Who are they?' is Kik ők? The verb must agree with the pronoun's plurality: ki takes a 3rd-person singular verb (Ki jön? - Who is coming?), while kik takes a 3rd-person plural verb (Kik jönnek? - Who [plural] are coming?). Additionally, all case suffixes can attach to the plural stem (e.g., kiknek - to whom [pl], kikkel - with whom [pl], and the accusative kiket).
• Case Suffixes: Because Hungarian uses cases, ki changes when the person is an object or target. Because 'ki' is treated as a front-vowel word, it takes the front-vowel variants of case suffixes (e.g., kinek, kivel, kiben). The accusative form is kit.
• Possession: To ask 'Whose?', you add the possessive predicate suffix -é to get kié (for a single object) or kiéi (for plural objects, e.g., Kiéi ezek a könyvek? - Whose books are these?). For plural owners, use kiké (singular object) or kikéi (plural objects). Alternatively, use the dative form kinek a... followed by the possessed object with its possessive suffix (e.g., Kinek a tolla?), or kiknek a tolla? for plural owners. Native speakers often prefer this dative structure over kikéi.
• Word Order: In a question, ki (or its inflected form) usually occupies the focus position immediately before the verb. Crucially, this position forces verbal prefixes to split and move behind the verb (e.g., bemegy [goes in] becomes Ki megy be? [Who goes in?]).
• Compound Pronouns: ki serves as the root for many important pronouns, such as valaki (somebody), senki (nobody), mindenki (everybody), akárki (anybody), and the relative pronoun aki (who).
• Not to be confused with: Do not confuse the question word ki with the common verbal prefix ki-, which means 'out' (e.g., kimegy - goes out).
• Choosing from a Group: If you are asking 'which one' out of a specific group of people, use melyik instead of ki.