I have had a start with CS Cart Community and am in the process of building multiple sites which will in the future be upgraded to professional or, more likely, multi-store and have different languages for each page (I will be translating all pages and product text) and want each language to be associated with different regions. Is the recommended way to show the language in the URL so that search engines can easily identify which pages are relevant to which regions? I notice if you do this on the community edition it changes the pages for English (I would have thought that the show language would be just for the additional languages, so you could add languages without impacting on your current store - but it doesn't appear to work like this).
If I will have to change all the pages / links in the future, I would rather start now by showing language in the URL, however when I tested this I did have a lot of concerns about how it worked i.e. existing links to pages without the language in the URL were serving the home page when numbers or other characters were in the URL. This will also require .htaccess redirection to move existing pages to ones with the language in the URL, which didn't work as it was adding ?sef_rewrite=1 to the end of the URL (and bug fix to CS Cart for showing the home page for old links). Although it would be a pain, I would rather build the store in the format recommended for future language expansion (but cannot understand when you expand to add languages that CS Cart also adds the language to the existing store).
Would it be better if CS Cart was able to show languages in the URL for just the additional languages so existing stores can add languages without changing existing URLs and links? If CS Cart was to work like this in the future, we can build the store now without Language in the URL and then use this option when adding languages, without changing the existing site (which appears to be the logical expansion of a store).
this bug thread has quite some useful info.
http://forum.cs-cart.com/tracker/issue-2646-seo-add-on-a-duplicate-content-issue/
I personally choose to show the language as a folder in the url. Many big shops do this, it looks clear, you can redirect very easily (I have my domain in every language and for example: .de redirects to /de). this way I can advertise in with the domain extension of the country I’m advertising in, because people still seem to prefer a local extension.
Also, it’s less confusing when you are working on your shop 
I though it would be good to show the language in the URL for additonal languages but don't see why it should also do this for the default language of the store. If the default pages are left alone and the /fr/ etc are added for the additional languages, this would appear to be a more logical upgrade path. The bug fix to redirect to the default language for the home page appears to be the wrong way of solving the problem - my belief is that you don't want the language in the URL for the default language at all - just the additional ones. This way there wouldn't be duplicate content in the first place or a need to redirect the home pages or all the other pages which already have links to them when languages are added. Or am I missing something?