Dynamic link to same entry but in alternate language
Both SEOmatic for Craft 2 and SEOmatic for Craft 3 have built-in functions to give you these URLs. I'm not sure which you are using so...

For Craft 2: https://github.com/nystudio107/seomatic/wiki/15.-Utility-Filters-&amp;-Functions#getlocalizedurls

For Craft 3: https://github.com/nystudio107/craft-seomatic#helper-functions-seomatichelper