One way to remember it is that suits can be expensive - costy men ;)
I know that only works for THE suit, but it helps :)
I remember it by thinking that suits can be custom made - or kostym made, if you get my drift :)
Why does the 'y' in the verb 'tycker om' sound like the u in 'djuret', and the 'y' in kostymen sound like the i in 'Vi'? It's confusing me how to pronounce the y in any Swedish word that is in front of me. Are there rules for this specific letter?
You can study Swedish phonology with IPA and also ortagraphic details with IPA. Just wrtie "Swedish alphabet in IPA" in google; wikipedia has good explanations.
No, that's a false friend.
Kostym means suit.
Costume translates to dräkt, such as you'd wear to a costume party or for a special occasion.
The way I remember it is, in England a swimming suit is called a bathing costume... So, suit=costume=kostym
We tend to say swimming costume rather than bathing costume, but yes, we do use the word costume :)
I think kostym is the one you'll find at the Menswear Department, whereas when it's a skirt and a jacket, it will be called en dräkt. I've heard the word byxdräkt for women's pant suits. I'm not sure if you can find something called en kostym on the Womenswear side, but I guess you could.
I believe both are interchangeable. Gillar is a little more informal though.