I studied Phonetics and Linguistics as part of my MA course at Edinburgh University. There were many speech therapists and TEFL (Teaching English as a Foreign Language people) among the students, as well as many nationalities (sadly, no Scandinavians though).
We learned to represent speech using Phonetic Script, and to listen extremely carefully to various recordings of British regional accents and even other languages. Our tongues were sprayed with cocoa powder (!) and then we pronounced a certain plosive, after which a camera took a photo of the inside of the mouth, to see where our tongues had touched the palate.
There were fascinating short films of X-rayed faces of speakers, showing the most weird movements of the glottis, epiglottis etc during the speaking of, say, pharyngeal fricatives (Arabic has these). I was amazed at how enormous the tongue is, it's a huge organ!
All this is to explain that any Nordic people learning English in their own countries would probably not have access to all this fascinating stuff.
My husband now has the most complex and amusing accent imaginable. Malinke mixed with French and Broad Norfolk!