Visiting Lanzarote is an interesting situation for me linguistically, as I speak all three of the main languages that you hear on the island: English, German and Spanish.
Which language do you speak as a tourist? My rule of thumb is to use Spanish as much as possible – in supermarkets, shops and restaurants. Of course the people serving could speak to me in my mother tongue, but I find it better that way.
It can often be to my advantage as well. Some locals are more welcoming if you make an effort to speak their language. At Teguise market you can often get a better bargain for making the effort and an even better one if you are fluent in Spanish. In restaurants the waiter’s English may only extend to taking your order and presenting you with the bill – it may not extend to sorting out complaints.
Obviously if I’m talking to an English or German national, then I will talk to them in their language. But it gets very interesting when sitting in a restaurant where I talk in Spanish to the waiter, English to my parents and German to my wife! It can confuse the staff as well!
But it can also be very funny, as being able to read all three versions of the menu I often find translations that have gone wrong.
I just haven’t got round to learning Swedish yet…