I don't think you can create two same web templates in different languages, as web languages are set on web application level and I also think what you want isn't possible in earlier version of SharePoint except SharePoint 2013.
However there is something new in SharePoint 2013 known as Machine Translation Services in SharePoint 2013 which can be used to get translations directly from Microsoft, but I am not sure about the possible ways to use it the way you want to do.
Learn about the Machine Translation Service, which is a new service
application in SharePoint 2013 that provides automatic machine
translation of files and sites.
Applies to: SharePoint Server 2013
However I would recommend creating different web applications with different languages where applicable and in future custom code you can use resources, which will make your life way easier.
Edited on 07 03 2013
I came across another feature named as "Variation Feature" of SharePoint which can be of your interest.
The variations feature in SharePoint Server 2013 and SharePoint Online
makes content available to specific audiences on different sites by
syncing content from a source variation site to each target variation
site. When users visit the root site, they are redirected to the
appropriate variation site, based on the language setting of their web
browser. Content on a target variation site can be translated into
other languages before it is published. Variations can be used only on
sites that are created by using one of the Publishing site templates,
or on sites for which the SharePoint Server Publishing Infrastructure
feature was activated.
Edit: Mark I haven't been on here long enough to make comments, but I wanted to note a few things. I believe Variations must be setup in order to use the Machine Translation service. Also languages can be set per site/sub-site (based on the available languages). The UI can language can be changed under site settings.