Mastering Masculine Nouns in Icelandic: A Quick Cheat Sheet

Icelandic grammar is famous for its complexity, especially when it comes to declensions (beygingar). If you are struggling to remember how masculine nouns (karlkyn) change, you are not alone.

This guide breaks down the three main groups of masculine nouns based on a helpful summary chart. We will look at the patterns, the "vowel shifts" (hljóðvarp), and the common irregularities.

The Big Picture: Strong vs. Weak

Masculine nouns are generally divided into two main categories:

1. Strong Nouns (Sterk beyging): These end in a consonant in the genitive singular (usually -s or -ar). This includes groups KK 1 and KK 2.

2. Weak Nouns (Veik beyging): These end in a vowel in all singular cases (usually -i, -a, -a, -a). This is group KK 3.

KK 1: The "-ar" Plural Group

Examples: Hestur (horse)

This is often considered the "standard" strong masculine declension.

Key Feature: The singular usually ends in -s in the genitive, and the plural always ends in -ar.

Vowel Shifts: There is usually an A-shift (u → a) in the plural.

Case	Singular (Et.)	Plural (Ft.)
Nf.	Hestur	Hestar
Þf.	Hest	Hesta
Þgf.	Hesti	Hestum
Ef.	Hests	Hesta

KK 2: The "-ir" Plural Group

Examples: Gestur, Fundur, Bær, Hver, Þáttur, Sonur, Köttur, Fjörður

This is the largest and most complex group. It contains many common nouns that undergo vowel shifts.

Key Feature: The plural ending in Nominative is -ir.

Grammar Note: Many of these words experience B-víxl (U-umlaut), where the vowel a changes to ö (or u) depending on the ending.

Common Patterns in KK II

A. Standard "-ir" Plural (Gestur, Fundur)

Words like Gestur (guest) and Fundur (meeting) follow a standard pattern but take -ir in the plural nominative and -i in the plural accusative.

Case	Singular (Et.)	Plural (Ft.)
Nf.	Gestur	Gestir
Þf.	Gest	Gesti
Þgf.	Gesti	Gestum
Ef.	Gests	Gesta

Case	Singular (Et.)	Plural (Ft.)
Nf.	Fundur	Fundir
Þf.	Fund	Fundi
Þgf.	Fundi	Fundum
Ef.	Fundar	Funda

B. The "J-Innskot" (The inserted J)

Example: Bær (town) Some words are "short" but insert a j before vowel endings in the plural.

Singular: Bær, Bæ, Bæ, Bæjar
Plural: Bæjir, Bæji, Bæjum, Bæja

Other words with J-innskot: Drengur (boy), bekkur (bench), hringur (ring), veggur (wall), leikur (game), drykkur (drink), lækur (stream).

C. The Vowel Shifters (B-víxl / U-Umlaut)

This group includes words where the root vowel changes.

Þáttur (Episode/Part): á shifts to æ in the dative singular (þætti) and plural (þættir).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Þáttur	Þættir
Þf.	Þátt	Þætti
Þgf.	Þætti	Þáttum
Ef.	Þáttar	Þátta

Sonur (Son): The vowel o shifts to y in the dative singular (syni) and plural (synir).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Sonur	Synir
Þf.	Son	Syni
Þgf.	Syni	Sonum
Ef.	Sonar	Sona

Köttur (Cat): The vowel ö shifts back to a in the genitive (kattar) and e in the plural (kettir).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Köttur	Kettir
Þf.	Kött	Ketti
Þgf.	Ketti	Köttum
Ef.	Kattar	Katta

Fjörður (Fjord): A classic example of complex shifting. Fjörður → Firði (Dat. Sg) → Fjarðar (Gen. Sg).

Case	Singular (Et.)	Plural (Ft.)
Nf.	Fjörður	Firðir
Þf.	Fjörð	Firði
Þgf.	Firði	Fjörðum
Ef.	Fjarðar	Fjarða

KK 3: The Weak Nouns (-ur)

Examples: Nemandi, Bóndi, Frændi

These are the easiest to learn! They are "weak" because they don't have the strong consonant endings in the singular.

Key Feature: They end in a vowel in all singular cases.

The Pattern:

Nominative: -i

Accusative, Dative, Genitive: -a

Case	Nemandi (Student)	Bóndi (Farmer)	Frændi (Cousin)
Nf.	Nemandi	Bóndi	Frændi
Þf.	Nemanda	Bónda	Frænda
Þgf.	Nemanda	Bónda	Frænda
Ef.	Nemanda	Bónda	Frænda

Plural: They all take -ur in the nominative plural (Nemendur, Bændur, Frændur). Note the vowel shift in the plural for Bóndi (ó → æ) and Nemandi (a → e).

Case	Nemendur (Students)	Bændur (Farmers)	Frændur (Cousins)
Nf.	Nemendur	Bændur	Frændur
Þf.	Nemendur	Bændur	Frændur
Þgf.	Nemendum	Bændum	Frændum
Ef.	Nemenda	Bænda	Frænda