Interrogative Words

An introduction to Irish question words like 'who', 'what', and 'where', and how they structure a question using the copula and relative clauses.

Interrogatives Questions Grammar Syntax

Interrogative words, or question words, are used to ask for specific information, such as “who”, “what”, “where”, and “why”. In Irish, these words have a distinct structure and syntax that is important for learners to understand.

While they can be classified as pronouns (cé - who), adverbs (cá - where), or adjectives (cén - which), this distinction is often blurred. Many interrogative adverbs are formed from pronouns, and many interrogative words can function in multiple roles. Syntactically, they all behave in a similar way.

A common feature of Irish question words is that they almost all begin with the letter “c”, such as cé, cá, and cad.

Historical note

The “c” in Irish question words originates from the same Indo-European root “kw-” that gives us “qu-” in Latin (quod), “wh-” in English (what), and “w-” in German (was). The Irish word cad (what) is a direct cognate of these examples.

Syntax of Question Words

The syntax of Irish question words is fundamentally different from English. They contain an implied form of the copula (is), meaning a word like cé functions as a complete clause: “who is”. This makes the entire question a copula sentence where the question word is the predicate.

If the question only involves the copula, the rest of the sentence is the subject.

Cé hé sin? - Who is that?
Cá haois dó? - How old is he? (Literally: “What age to-him?”)

If the question involves another verb (e.g., “Who says that?”), the subject of the copula sentence is a relative clause.

Cé a deir sin? - Who says that? (Literally: “Who-is [the one] who says that?”)
Cad a rinne sé? - What did he do? (Literally: “What-is [the thing] that he did?”)
Tuige ar tháinig tú annseo? - Why did you come here?

This structure is a core concept in Irish grammar and is essential for forming questions correctly.

Usage in Indirect Questions

Interrogative words are also used to introduce indirect questions. These are subordinate clauses that follow verbs of asking, knowing, thinking, or expressions of uncertainty.

Níl a fhios agam cé hé an fear seo. - I don’t know who this man is.
Smaoinigh mé roimh ré ar céard a déarfainn. - I thought beforehand about what I would say.
Ní raibh sé cinnte cad a déarfadh sé. - He wasn’t sure what he would say.
…féachaint cad a bhí le rá ag an údar. - …to see what the author had to say.

A Common Pitfall

Watch out

In English, question words like “what” and “who” can also function as relative pronouns (“I know what you did”). This is not the case in Irish. You cannot use interrogative words like cad in this way. Instead, you must use phrases like an rud a (the thing that) or the general relative pronoun a.

Avoid	Prefer
… cad a bhí uaidh	… a raibh uaidh
… cad a bhí tuillte acu	… an rud a bhí tuillte acu

Thug mé dó a raibh uaidh. - I gave him (everything) he needed.
Thug sé dóibh an rud a bhí tuillte acu. - He gave them what they deserved.

Usage in Exclamations

Irish question words can also be used in exclamatory sentences to express surprise or emphasis, much like “What a…!” or “How…!” in English.

Cad é mar thubaiste! - What a disaster!
Cad é mar atá an fear láidir ar lár! - How astonishing that the strong man is down!
Cad é a mhinice … - How often…!
Cad a bhfuil agam á fhulaingt laistigh! - What I have to suffer inside!

The main Irish interrogative words are detailed on the following pages:

cé (who, what, which)
cá (where, which, how)
cad (what)
céard (what)
conas (how)
cathain (when)
an (in certain “how” questions)