Joomla choosing wrong language? - Joomla! Forum - community, help and support

i running joomla 2.5.6 site swedish default site language - , have english installed. have language filter plugin activated. language articles set "all". still, seems joomla chooses english site language, giving url's

http://www.webblabbet.se/demo/index.php/en/

i confused. how joomla recognize swedish default language. can walk me through this? assistance appreciated.

please check default language @ admin-> extensions -> language manager -> installed site( tab).