When I started to set up nopcommerce for two languages, English and Persian, I noticed some problems in SEO 1. in http://ttbolt.com/fa/sitemap when I switch to language links are changed by language term in the url.example: language is en : http://ttbolt.com/en/anchor-bolt-hsc language is fa : http://ttbolt.com/fa/anchor-bolt-hsc
in no 3 for a long time we have duplicate content in google.Google crowls two pages with one content. :#(2.In sitemap : http://ttbolt.com/sitemap.xml we have two addresses for a page. by en and fa . maybe if we add another language it will add a new duplicate page in sitemap. very harmful for SEO.3.when we have no page in en lang for example. if we type the address by /en or /fa or /otherlanguage it must block the page with the wrong language. This has the potential to be harmful for SEO.