Change language by code

hello

 i have SharePoint site collection and i make variation on this for two language (English-Arabic)

and i but all list at root and i access it from sub-sites(Arabic -English)

but there is a problem when add item to list form display with it's root language not  subsite language (Arabic) and when i change root to Arabic sub site work fine ,but English sub-site (add item form ) apper in its root site (Arabic)

how can i solve it by code 

Nour