Learn Hardcore Icelandic: Myndin var góð í gær.

In Icelandic, the definite article is suffixed to the noun. Mynd means “movie” (or “picture”) and is a feminine noun. The nominative-singular definite suffix for feminine nouns is -in, so Mynd + -in = Myndin (“the movie”).

Why is the adjective góð placed after the verb instead of before the noun?

Because here góð is a predicative adjective linked by the verb vera (“to be”). Predicative adjectives come after the verb (e.g. Myndin var góð = “The movie was good”). Attributive adjectives that directly modify a noun come before it (e.g. góð mynd = “a good movie”).

Why is it góð and not góður or gott?

Adjectives in Icelandic agree with the noun’s gender, number, and case. Mynd is feminine, nominative, singular. The strong-declension forms of góður (“good”) are: masculine góður, feminine góð, neuter gott, and plural góðar. Hence góð for Mynd.

Why is the past tense of vera “var” and not something like was?

Vera is highly irregular. Its third-person‐singular past form is var, not was. For third-person‐plural past, it’s voru. There is no separate past stem w- as in English.

What does í gær mean and why include í?

Í gær literally means “in yesterday” but functions as the set Icelandic adverb for “yesterday.” You cannot drop í; gær on its own does not mean “yesterday” in standard Icelandic.

Can í gær be moved to the start of the sentence?

Yes. Icelandic follows a verb-second (V2) rule. If you put the time adverbial first, the verb still comes second:
Í gær var myndin góð.
(“Yesterday the movie was good.”)

How would I make the sentence negative?

Insert the negation particle ekki after the verb:
Myndin var ekki góð í gær.
That means “The movie was not good yesterday.”

How do you pronounce Myndin var góð í gær?

Rough phonetic guide:
Myndin [ˈmɪn.tɪn]
var [var]
góð [kouːð]
í [iː]
gær [kair]
So altogether: [ˈmɪn.tɪn var ˈkouːð iː ˈkair].