Partially Multilingual
This module helps multilingual websites by redirecting visitors from untranslated pages to their source language equivalent. This prevents duplicate URLs for the same content, improving search engine optimization.
Quick Summary
If you have a site that is multilingual, but only some pages are translated, this module redirects untranslated pages to the source language, to help with search engine optimization.
There is currently not a stable release covered by the security policy. See
#3023523: Make a stable release with security compliance
#3233562: Abandoning Partly Multilingual
The original developer of this project was jhodgdon. Joseph Olstad is now maintainer.
A similar more popular module exists
The similar module is called Content Translation Redirect
Feel free to evaluate both and provide feedback.
A bit more detail...
The purpose of the Partially Multilingual module is to avoid having multiple, unaliased URLs for the same page, which differ only by the language prefix in the URL, if your site has pages that are not translated into all of the enabled site languages.
Without this module, for example, if a site visitor is viewing the site in Spanish, and clicks through to a page that is only available in English, the visitor will most likely see a URL like /es/node/77, while the page content will be in English, and matches the content that would also be available at the URL /about (assuming that is the English page alias). This situation is not good for search engine optimization (SEO).
With the Partially Multilingual module installed, in this situation, the site visitor will instead be redirected (permanently) to the /about URL, so that /about will be the only URL that has this content.
There is no configuration in this module. By having this module installed, it will monitor incoming URLs. If the URL corresponds to viewing a regular Content (node) page that is not translated into the requested language, the URL will be redirected (with a permanent/301 code) to the URL for viewing the content in its source language. (In the example above, if you go to /es/node/77, you will be redirected to /about.) If the URL is for some other type of page, or the requested language exists for this content item, the request is not redirected.
For more discussion about this situation, the original author of this module wrote up a blog post: http://poplarware.com/article/partially-multilingual-seo