In the system configuration there is no module to switch the language site in the user part. This is because it is impossible to foresee whether it is necessary and how shoud be documented. To implement selection of the language, you can use ready-made plug-in or write it yourself. When writing your own plug-in you must take into account the peculiarities of the system.
To select the language you can use 2 ways.
1. Using the SEF URLs. Explicitly specify the language in SEF URL as it appears in the administrative part, using the fully qualified host name, and immediately after the host name.
Examples:
http://mysite.com/en/
http://mysite.com/en/news/
http://mysite.com/ru/
http://mysite.com/de/
2. Using passed by GET or POST parameter 'ulch'.
Examples:
http://mysite.com/?ulch=ru
http://mysite.com/en/?ulch=ru
http://mysite.com/en/news/?ulch=de
http://mysite.com/ru/?ulch=en
http://mysite.com/de/?ulch=ru
Transmission choice of language through the parameter 'ulch' has a higher priority. This means that if the choice of language will be specified once by both ways, then the language will be chosen which is specified in the parameter 'ulch'.
If there is no clear guidance on the choice of language when the page is loaded, the constant value u_lang_default will be used.