Hi Gula,
In SharePoint 2013, after you install language packs, add the second language into the additional language of the site, then the language of the SharePoint site is based on the language of your brower. For example, your SharePoint deafult language
is English, after installing Chinese pack for your SharePoint, if your browser language is Chinese, the language of the site is Chinese.
More information:
https://olafd.wordpress.com/2012/11/02/switch-language-in-sharepoint-2013/
In addition, if you are using variation, you can enable VariationsLabelMenu, then there will be a language dropdown menu in your publishing site.
More information, please refer to:
https://social.technet.microsoft.com/Forums/en-US/51d49f03-966c-476f-bdf2-91ef1c5831f7/variationslabelmenu?forum=sharepointdevelopment
Thanks,
Wendy