No matter how natural Swedes sound when speaking English, their pronunciation often gives them away. One common example is the ‘z’ sound, which doesn’t exist in Swedish. It’s a dead giveaway when Swedes pronounce ‘muzic’ as ‘musssic’, say ‘pleasse’ instead of ‘pleaze’, ‘wass’ instead of ‘waz’. Their ‘s’ is pronounced as in the word sit.
It’s a classic mistake made by many international recording artists (Nina Persson, Marit Bergman, Abba, Moneybrother to name but a few) and it gives them away immediately.
This mispronunciation can lead to mísunderstandings too. One story I heard is about a Swede and an Irishman who met for the first time. The conversation went something like:
Swede: “You’re not English are you?”
Irish: “No, I´m from Ireland.”
Swede: “Yes, I thought I could tell from your R:s.”
The Irishman was confused and wondered how his nationality was obvious by looking at his arse.