In English, there are countable nouns and uncountable nouns. An example of a countable noun in English is “cat”. It is considered a countable noun because there can be one or several instances of “cat”. Uncountable nouns, such as “music”, cannot have several instances – you cannot have *”one music” nor *”two musics”. It’s just called “music”. Some nouns can even be countable and uncountable at the same time, such as “[I bought] soda [at the store]“, “[I bought] a soda [at the store]“.
In Swedish, the same rules apply. You can have en katt or två katter without issue, while like in English, you cannot have *en musik nor *två musiker. (Don’t get the made-up word *musiker confused with the real word musiker, which means “musician”.) The word for “soda”/”pop”/”soft drink” in Swedish is läsk[en], and just like in English, this word can be either countable or uncountable: [Jag köpte] läsk [i affären], [Jag köpte] en läsk [i affären].
Most of the words that are countable, uncountable, or both in English are also countable/uncountable/both in Swedish. One thing that Swedish has that English does not, however, is noun gender. And gender occasionally likes to be weird. Take for example the word öl, or “beer”; in uncountable form it is a neuter word (öl[et]), while in countable form it is a common word ([en] öl).
Ölet vi drack hos Mange igår smakade äckligt. – The beer we drank at Mange’s [place] yesterday tasted gross.
Jag tog en öl hos Mange igår. – I took a beer at Mange’s [place] yesterday.
A similar case is the word godis, or “candy”, “sweets”:
Vi åt godis[et] när vi var på bio. – We ate [the] candy when we were at the cinema.
Ta en godis/några godisar från godispåsen. – Take a candy/some candies from the candy bag.
But this is far from always the case – läsk, as shown earlier, retains its common gender in both countable and uncountable form ([en] läsk; läsken).
(Please note that countable and uncountable form are not the same as indefinite and definite form, respectively. Countable means that the object can be counted – “one cat”, “two cats”, “the cat”, “the cats”. Uncountable means that the object (often abstract) cannot be counted – *”one music”, *”two musics” but “the music”. Indefinite vs. definite form, on the other hand, make up the difference between “a cat” and “the cat”; “two cats” and “the cats”; “music” and “the music”.)