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Hi,
You need to categorize them as canonical url's (rel=canonical ), you can do this pretty simply in CMS's like Magento etc. - just Google for a guide 
“Canonical links”, is an HTML element that helps webmasters prevent duplicate content issues. It does this by specifying the “canonical URL”, the “preferred” version of a web page. Using it well improves a site’s SEO. Source
Yes you would face DC. I would recommend to use Google search console and tell Google you now have a new language on the same site. This should do the work for you as far as I know.
Hi,
You need to categorize them as canonical url's (rel=canonical ), you can do this pretty simply in CMS's like Magento etc. - just Google for a guide
“Canonical links”, is an HTML element that helps webmasters prevent duplicate content issues. It does this by specifying the “canonical URL”, the “preferred” version of a web page. Using it well improves a site’s SEO. Source