Learn Hardcore Icelandic: Garðurinn er stór og grænn.

In Icelandic the definite article is suffixed to the noun. garður means “garden” (indefinite) and garðurinn means “the garden” (masculine singular definite nominative). The ending -inn marks definiteness.

Why do stór and grænn end in -r (and have a double n)?

They are predicate adjectives (they follow the linking verb er) and therefore use the strong (indefinite) declension. In masculine nominative singular strong declension, stór takes -r and grænn has a double -n in its stem.

Why don’t the adjectives take a definite form since garðurinn is definite?

Only attributive adjectives (those placed before the noun) take weak (definite) endings. Predicate adjectives (after er) remain in the strong (indefinite) form, even when the noun they describe is definite.

How do you say “the big green garden” with the adjectives before the noun?

Use attributive adjectives with weak endings. For masculine nominative singular you get stóri græni garðurinn. Both stóri and græni end in -i because the noun is definite (marked by -inn).

Could the adjectives change if garður were a different gender?

Yes. Adjectives agree in gender, number, and case. For example, with a neuter noun like hús you’d say húsið er stórt og grænt; with a feminine noun like bók you’d say bókin er stór og græn.

What does og mean and how is it used here?

og is the conjunction “and”. It connects the two adjectives just like in English: stór og grænn = “big and green”.

How do you pronounce Garðurinn er stór og grænn?

Stress falls on the first syllable of each word. Approximate IPA:
Garðurinn [ˈkar̥ðʏrɪn], er [ɛːr], stór [stouːr], og [ɔɣ], grænn [ˈkrai̯n].
Here ð is like the “th” in “this” and æ like the “i” in “ice”.

How would you form a yes/no question from this sentence?

Invert verb and subject: Er garðurinn stór og grænn?
Answer with Já, garðurinn er stór og grænn (“Yes, the garden is big and green”) or Nei (“No”).