I have a bi-lingual website with a sitemap index for each language that links to several different sitemaps (one for videos, one for static content, and one for articles). I would like to introduce another sitemap that links the sitemap indexes, so I could link that sitemap in the robots.txt in the root and wouldn't have to have one robots.txt for each language.
Is that valid? Or is there a simpler solution to my problem?
I'm not sure if this changed over the years since this was asked; while in theory you can (as the first answer states), in practice Google at least will give you an error (as seen in their Webmaster Tools):
Incorrect Sitemap index format: Nested Sitemap indexes
The Google help page further states:
A sitemap index file can't list other sitemap index files, but only sitemap files.
Source: https://support.google.com/webmasters/answer/7451001#errors (note you'll have to expand the 'complete error list')
Yes, you can have a sitemap index containing references to other sitemap indexes [source], as long as they're all on the same domain.
Updated: Sitemap index files can't contain other index files – each sitemap index can contain links to regular sitemaps. Multiple sitemap indexes can be submitted to Google individually, though.
Each individual sitemap index can include up to 1,000 references to another <sitemap>. If you need to reference more than that, create multiple sitemap indexes and submit each one.
Each individual sitemap can include up to 50,000 page references. If you need more than that, split them across multiple sitemaps.
There is an easier way but only if your web hosting package allows it.
Why not create subdomains for each language?
Each subdomain can then be pointed to a separate folder then basically, you copy everything so both folders are identical, then you change the contents of the newly presentation pages (for example, index.html) to match the different language.
For example, if you have a setup like this:
URL: http://www.example.com
Document root of above URL: /home/user/public_html
Contents of document root:
index.html
index.css
sitemap.xml
robots.txt
Then you can plan a setup like this:
URL: http://fr.example.com
Document root of above URL: /home/user/french/public_html
Contents of document root:
index.html
index.css
sitemap.xml
robots.txt
Then you'd only change index.html.
BUT...
If you used absolute pathnames in some of your scripts, then you need to change those as well. so in the above example, if the copy of index.html refers to index.css in the original folder, then that needs to be updated.
