Swedish has several ways to say that someone is in a bad mood. You can be a little irriterad because someone is chewing too loudly. Sur because the coffee has run out. Arg because the train has been cancelled. And förbannad when the train has been cancelled, the coffee has run out and someone is still chewing too loudly. The words are related, but they do not feel the same. They sit at different points on the mood scale, from a slight crease between the eyebrows to the sensation...

Swedish has plenty of ways to talk about plans. We plan dinners, meetings, trips, workouts, phone calls and small, ambitious projects that begin with the words “det vore kul att” (“it would be nice to…”). Then life happens. Someone gets ill. The train is delayed. It starts raining sideways. Nobody books a table. Everyone is tired. One person writes “vi hörs sen” (“speak later”), and suddenly three months have gone by. That is when Swedish particle verbs come to the rescue.

To someone seeing Swedish Midsummer from the outside, the whole thing may seem fairly sensible at first. It is summer. The days are long. People gather outdoors, eat together and put flowers in their hair. Then fully grown adults begin hopping around a leafy pole while singing about frogs with no ears and no tails. That is roughly where Midsummer becomes more interesting. Midsummer is one of Sweden’s biggest celebrations. It takes place in June, close to the longest day of the year, when...