The questions related to the title are multifold as follows,
In this article the late Suhotra Swami quotes Bhavishya Purana saying that Mlecchas are descended from Adama and Havyavathi who are children of Rishi Kardama. Are the above claims about Mlecchas and their religion and lineage of prophets prophets really present in the Bhavishya Purana? Is there a authentic verison of this Purana available online?
Is there any other Purana which talks about the origins of Mlecchas and about Adama, Havayavathi lineage? Does Bhagavata Purana or Mahabharatha has references to the same?
In the Mahabharatha, many Mleccha tribes are mentioned like Sakas, Huns, Yavanas(Greek), Kambojas, Pahlavas, Bahlikas, Rishikas, Chinas(China), etc, etc. Are connections made to Greeks, Syrians, Chinese, etc mere conjecture or has the Mahabharatha mentioned any Capital cities, traditions, languages or practices which directly like these Mleccha tribes to the present day nation states?
[Here] is an (http://hindudharma.quora.com/Rarely-known-secrets-about-Hinduism) interesting read on this regard which prompted some of the above question.