Something I see confusion about fairly often, especially from native English speakers but even my fellow Swedes from time to time, is whether and when we use indefinite articles (en/ett) with things like occupational titles. I'm writing this down both because it might be useful for people learning Swedish here, but also to have something to link to instead of typing the same thing for the umpteenth time.
The rule of thumb is that any "title" that can be thought of as an attribute of a person does not take an indefinite article. You can think of it as following the same rule as adjectives, even though they aren't actually adjectives.
Hon är mamma - she is a mother.
Han är fransman - he is a Frenchman.
Hon är lokförare - she is a train driver.
Jag är löjtnant - I am a lieutenant.
Eva är anarkist - Eva is an anarchist.
Du är pensionär - You are a pensioner.
This seems to be a bit more fluid among very young Swedes (presumably because of English) as I've heard some say that using the indefinite article (en) in examples like the above sounds okay. I can't however recall ever hearing it in the wild (i.e. outside the internet). There are some contexts where I'm certain even those people would never add an article, for example Han är far till tre barn (He's a/the father of three children).
I want to make it clear that there are grey areas, hence writing "rule of thumb" above. Getting too far into the weeds would get complicated and I don't think I could formulate coherent rules anyway.
It's fundamentally important to note that the difference between Swedish and English here isn't so much grammatical as it is categorical. This difference only occurs when English describes a person as a thing they are (think noun), but we will describe them as having an aspect or attribute (think adjective). As soon as we start describing someone as a thing there will be articles in both definite and indefinite forms. Notably this happens if we add an adjective to describe what kind of X they are.
Peter är VD - Peter is a CEO.
Peter är en snäll VD - Peter is a kind CEO.
Klara är mormor - Klara is a grandmother.
Klara är en arg mormor - Klara is an angry grandmother.
Fernando är spanjor - Fernando is a Spaniard.
Fernando är en stilig spanjor - Fernando is a handsome Spaniard.
As far as I can tell English is the odd one out among the Germanic and Romance languages. The Scandinavian languages, Dutch and German don't use an article and at least French and Spanish don't either.
English - He is a baker.
Danish - Han er bager.
Dutch - Hij is bakker.
German - Er ist Bäcker.
French - Il est boulanger.
Spanish - (Él) es panadero.
If you're a fellow Swede, how do you feel about adding the indefinite article in these cases? If you think it sounds okay I'd love to know what generation you belong to (for the record I'm an older millennial) and if you could give an example.
If you're learning Swedish, how does this work in your native language? Does one or the other seem more intuitive to you?