Basically you need to translate the phrases.php file or create a new language in the application which will clone the english strings. Set your language to swedish then you can translate each string in the admin panel.
This is what I would do. There are translated languages in the classifieds language forum that show what I am saying.
1. Take phrases.php and rename it to swedish.php
2. Open up that new swedish.php file and replace any reference to phrases.php to swedish.php
3. You can then translate each string like so translating the first reference which is the text. The second string is the original. You can translate that to swedish also if you want I usually suggest people leave that as english incase they mess that up. The second string is the original text to revert to in the app if you mess up a translation in admin panel
see the part to translate here
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