Learn Swedish: Jag har fått dina sms, men jag hittar inte pdf:erna i dem. - I have received your text messages, but I do not find the PDFs in them.

In Swedish, when you add grammatical endings (like plural or definite articles) to an initialism, you connect them with a colon. The base word is pdf, and we add the definite plural suffix -erna to mean 'the PDFs', resulting in pdf:erna.

Why isn't there a colon in sms if it means 'text messages' in plural here?

You only use a colon when you actually attach a suffix to the word. Because sms is an ett word ending in a consonant, its indefinite plural form is exactly the same as the singular (ett sms, flera sms). Since no extra letters are added, no colon is used.

Why are sms and pdf written in lowercase letters?

Unlike English, which usually capitalizes initialisms like SMS and PDF, Swedish generally writes them in lowercase when they are established as common, everyday nouns.

After the possessive word dina, shouldn't the noun be definite?

This is a common mix-up! In Swedish, nouns following a possessive pronoun (like min, din, dina) must always be in the indefinite form. Here, dina tells us it is plural, so we use the indefinite plural form of the noun, which is just sms.