Any suggestions on why this 'Swedenizing' ?
Seems obvious to me. They wanted to sell them in the Swedish market. And Swedish-language labels make particular sense at a time when most of Europe did not speak/read/write English.
In Denmark, I've come across various examples of similar "local" versions of recordings by non-Danish (American, British, German) artists. Not yet any with concertina, though.
Goran Rahm replied on the 78rpm Community thread:-
This label ( and possibly others - maybe you know? ) most certainly was directed to the market among swedish immigrants in USA, particularly in Minnesota.It has been suggested that it was targeted to the market in Sweden but that is very unlikely since at the time there was very limited interest for this kind of music in Sweden. Recorded accordion music had been introduced in Sweden around 1911 by the brothers Oscar and Ragnar Sundquist. Oscar visited London 1911 and brought an english system concertina back used firstly by his son Sven with whom e couple of recordings were made in London 1914 on the label "Sundquist records". This likely was the first public commersial presentations of concertina in Sweden. Apart from that british concertinas were known in Sweden exclusively in relation to Salvation Army. Otherwise there was only a minor import of german concertinas but they were hardly noticed compared to the immense import of harmonicas and melodeons from Germany.
So he's suggesting that this release was directed at Swedish immigrants in the USA, rather than folks in Sweden. But I went searching for those titles I saw a few years ago, and found that they weren't for Prince, but James Hume and around 1918. If you go to CHARM and type James Hume into the performer field, you'll find 3 pages of results, with Scandinavian titles taking up a lot of the last two pages.