Bilingual website:setting the language version needed

Hello!
I have a bilingual website on wordpress with the qTranslate plugin.
The question is how to change the default language of the site that a visitor sees. For example, the two languages of my website are Russian and Estonian. As it is now set, the visitor gets the Russian version of the website when he gets there and what I want is the Estonian version to come first.
I have asked my developer to change the languages but he seems to be very busy to make it done.
Any help would be appreciated.
Thanks.