You already know that Swedish nouns have one of two genders: common (en-words) or neuter (ett-words). When we use an adjective to describe a noun, that adjective needs to change its form to match the noun's gender. This is called agreement.

Let's start with the easy one. When you describe a singular, indefinite en-word, you just use the adjective's base form. No changes needed.

• en stor bil (a big car)
• en glad hund (a happy dog)
• en ny bok (a new book)

This is known as strong declension, which is used when there's no definite article like 'the' or 'this' telling the adjective what to do. The adjective itself has to do the grammatical work.

Things change slightly for ett-words. To make an adjective agree with a singular, indefinite neuter noun, you almost always add a -t to the end of its base form.

Adding a '-t' is straightforward most of the time, but Swedish spelling has a few quirks to keep things interesting. These rules pop up when an adjective's base form ends in certain letters.

First, if an adjective ends in a stressed vowel, you double the consonant before adding the ending. In this case, you add -tt instead of just -t.

• ny (new) → ett nytt jobb (a new job)
• blå (blue) → ett blått öga (a blue eye)
• fri (free) → ett fritt land (a free country)

Next, if an adjective's base form ends in a -d, the -d changes to a -t for the neuter form. This is a common sound shift. An adjective ending in a vowel followed by a -d will therefore get a -tt ending.

• god (good) → ett gott vin (a good wine)
• röd (red) → ett rött äpple (a red apple)
• glad (happy) → ett glatt barn (a happy child)

If an adjective already ends in a '-t', you don't need to add another one. It stays the same.

• lätt (easy/light) → ett lätt prov (an easy test)
• svart (black) → ett svart bälte (a black belt)

Finally, there's consonant doubling for some adjectives ending in '-n' or '-m'. If an adjective ends in an unstressed '-en', the '-en' is dropped before adding the neuter '-et'. However, for adjectives ending in a vowel followed by '-m' or '-n', the consonant is often doubled.

• dum (stupid) → ett dummt skämt (a stupid joke)
• tunn (thin) → ett tunnt täcke (a thin blanket)

This might seem like a lot of small rules, but they quickly become second nature with practice.

Let's check your understanding of these adjective rules.

Mastering these forms is a key step. You can now describe any single object you encounter in Swedish.