[TYPO3-english] config plugin.tx_srlanguagemenu_pi1 on introduction package

[Task City]

Hello! Everyone,

I'v installed more than three languages for people to view my website, but there is a problem that language can't be selected on introduction package except English & Danish in default configration. The URL is as same as default language when I choose others. I don't know why.  Has someone can tell me how to solve the problem.

Thanks and Wishes!
Jeson