Please let me introduce my own solution... (Oh, if I just have seen this topic before!)
I made snippet/plugin works together to handle multilingul pages.
please see the page below for details.
http://nanabit.net/modx/multilingual-listing-en.html
(or in Japanese:
http://nanabit.net/modx/multilingual-listing.html)
First, the snippet Multilingual Listing makes a switching list like the solution above.
The difference is, this one searchs identical document but written in other languages by
aliases, like ’doc’, ’doc-fr’, ’doc-ja’,.., not by TVs.)
Next, the plugin Multilingual Router devides the access by looking up Accept-Language
HTTP request header. It attempts to find the document in specified language, and if found,
sendForward(..) to it.
This function contradicts to the first one, so if the visitor is from same document(but in
another language), the plugin does nothing.
Finally, the total difference between the solution above and this one is,
that the latter enables the site owner to provide alternative language at the pinpoint documents.
If my understanding is correct, with the former way, all alternative languages’ page
should be provided.
In this way, if the requested language version does not exist, the visitor will simply receive
the original language version. So they can translate it by their own (with web translation services).
I think the former method suits for formal cases that all pages should completely written in the
requested language, and this method would suit rather informal and incomplete (yes, the only
document-content is alternative. Even though the visitors select another language, templates
, chunks and so on do not alter.

) cases that the site owners who want to provide to the visitors
a glimpse of the document in a few pages.
Thanks,