Learn Hardcore German: Hat irgendjemand meinen Schlüssel gesehen?

Yes/no questions in German begin with the finite verb. In the perfect tense, the auxiliary hat comes first, then other elements, and the past participle gesehen goes to the end: Hat … gesehen?

Why is it hat and not haben?

The subject is irgendjemand (someone), which is third-person singular, so the auxiliary is hat. If the subject were plural (e.g., Leute), you would use haben.

Why is gesehen at the end?

In the Perfekt, the past participle goes to the end of the clause. Together with the auxiliary, German forms a sentence “bracket”: hat … gesehen.

Why use the perfect (hat gesehen) instead of the simple past (sah)?

In everyday spoken German, especially with strong verbs like sehen, the Perfekt is preferred. Sah jemand meinen Schlüssel? is grammatical but sounds literary, journalistic, or regional.

What’s the difference between jemand, irgendjemand, irgendwer, and niemand?

jemand = someone (neutral, most common).
irgendjemand = anyone at all / someone or other (emphasizes “no matter who”).
irgendwer = colloquial alternative to irgendjemand.
niemand = no one. Also possible: irgendeiner (colloquial/pronoun), e.g., Hat irgendeiner …?

Is irgendjemand one word?

Yes, it’s a single compound word. Don’t write irgend jemand. Other irgend‑ compounds include irgendwann (sometime), irgendwo (somewhere), irgendwas (something, colloquial).

What case is meinen and why isn’t it mein?

Meinen is accusative masculine. The verb sehen takes a direct object in the accusative. Since Schlüssel is masculine (der Schlüssel), the possessive mein declines to meinen: meinen Schlüssel.

How would it change if I meant “keys” (plural)?

Use plural accusative: meine Schlüssel. The noun form doesn’t change (singular and plural are both Schlüssel), so the determiner shows number: Hat irgendjemand meine Schlüssel gesehen?

Can I move parts around, e.g., Hat meinen Schlüssel irgendjemand gesehen?

Yes. In yes/no questions, anything can occupy the “middle field” between the first verb (hat) and the participle (gesehen). Different orders can add emphasis, but all are grammatical:

Hat irgendjemand meinen Schlüssel gesehen? (neutral)
Hat meinen Schlüssel irgendjemand gesehen? (emphasis on the object)

How do I ask “Who saw my key?” instead?

Use a wh-question with wer: Wer hat meinen Schlüssel gesehen? Here, wer is the subject, so the verb is still hat.

How do I add ideas like “yet,” “ever,” or “by any chance”?

“yet/already”: schon — Hat jemand schon meinen Schlüssel gesehen?
“ever (at any time up to now)”: schon mal (colloquial) or jemals (more formal) — Hat jemand meinen Schlüssel schon mal gesehen?
“by any chance”: zufällig — Hat zufällig jemand meinen Schlüssel gesehen? You can also add vielleicht (maybe) for politeness.

How do I negate it (“Has no one seen my key?”), and is double negation a thing?

Negative subject: Hat niemand meinen Schlüssel gesehen? or Keiner hat meinen Schlüssel gesehen.
German standardly avoids double negation for the same idea; don’t say Hat niemand nicht …. However, Hat nicht jemand …? means “Hasn’t someone …?” (a hopeful/rhetorical question).

Why does sehen use haben and not sein in the perfect?

Most transitive verbs (those that take a direct object), including sehen, form the perfect with haben. Sein is mainly for intransitive verbs of motion or change of state (e.g., ist gegangen, ist geworden).

Any pronunciation tips for the tricky parts?

sch in Schlüssel = English “sh”.
ü in Schlüssel is a front-rounded vowel; say English “ee” while rounding your lips.
j in jemand = English “y”.
irgend is often pronounced with a very light vowel in the middle: roughly “IR-gənd”.
gesehen has a long “e” in the stressed syllable: ge-ZEH-en.

Are capitalization and spelling here special in any way?

Nouns are capitalized, so Schlüssel is uppercase; irgendjemand is lowercase. Irgendjemand is written as one word. Note the umlaut in Schlüssel; it’s not Schussel. End with a question mark for the yes/no question.

Is Schlüssel always “key,” or could it be a tool?

Der Schlüssel by itself means “key” (for a lock). The tool is der Schraubenschlüssel (wrench/spanner). Context usually makes it clear.

Do I need to inflect jemand/irgendjemand in other cases?

Yes, in standard usage:

Nominative: (irgend)jemand
Accusative: (irgend)jemanden
Dative: (irgend)jemandem
Genitive: (irgend)jemandes In casual speech, some speakers omit the -en in the accusative, but the inflected forms are preferred in writing.

Are there regional/colloquial alternatives?

Yes:

Hat jemand meinen Schlüssel gesehen? (most common)
Hat irgendwer meinen Schlüssel gesehen? (colloquial)
Austrian/Bavarian colloquial: Hat wer meinen Schlüssel gesehen? All mean essentially the same thing, with slight differences in register.