I have a brother. He lives in Sweden. I have another brother. He lives in the US.

These are four acceptable English sentences. If I was describing my family to you, you would know exactly what I was talking about. I would have conveyed meaning. You may also have found this manner of speaking to be very stilted. Instead of starting a new sentence each time I wanted to give you new information about my brother and continuing this somewhat stilted manner of speech, I might instead use a relative pronoun. Like “who”:
I have a brother WHO lives in Sweden. I have another brother WHO lives in the US.

That one simple word cut four sentences down to two and gave it a much better flow. We can do the exact same thing in Swedish. And we will.

When we first start learning Swedish, we are using these simple sentences. And it’s something that is necessary and useful. But as we continue to learn the language, frustration often sets in as we are limited by what we can and can’t say. Our language feels stilted. And it probably is. Let’s describe someone else’s family then in that classic (yet choppy) way:
Jag har en bror. Han bor i Sverige. Jag har en syster. Hon är lärare.

In Swedish, we can use som as a relative pronoun. It takes the place of “who” in English (and “that” and “which” for that matter) and refers back to the noun in the first sentence. So let’s take those choppy sentences and use a relative pronoun to make it flow just a little bit better:
Jag har en bror SOM bor i Sverige. Jag har en syster SOM är lärare.

Ta da! It’s that easy. What we’ve done from a grammatical standpoint is take two main clauses (Jag har en bror. Han bor i Sverige) and instead created one main clause and one relative or sub clause. Som doesn’t change. It is going to be som regardless of the gender or plurality of the noun we are referring back to. For example:
Han bor i ett hus SOM är stort. – Hus is of course an ett word, but you’ll notice som doesn’t change.
Hon har en hund SOM är stor. – Hund is an en word, but, again, som doesn’t change.
Han bakar kakor SOM är stora. – Kakor is plural, but, no surprise here, som doesn’t change.

Let’s take a look at a few more examples:
Han skriver med en penna SOM han fick från läraren.
Hon rider en häst SOM heter Jolly Jumper.
Hon är gift med en kvinna SOM är 26 år gammal.

You’ll notice that in each of these sentences, som refers back to the noun in the main clause (en penna, en hast, en kvinna) and helps to give us more information about the noun.

Now it’s your turn. Write a sentence or two using som in the comments below. Lycka till!