The Torah begins its list with the children of Yefes, because he was the Bechor (Ramban to Bereishis 6:10; Rashi to 10:21). But why does it continue with the sons of Cham, and not of Shem (who was older than Cham according to Ramban)?
Ramban: It is appropriate to list the sons of Shem last, since the rest of the Torah deals with the sons of Shem. 1
Rashi writes:"Tiras - this is Paras (Persia)." How does Rashi know this?
Gur Aryeh: Madai (Media) is another son of Yefes listed in this verse. Paras and Madai must stem from one source, as they later established a joint kingdom.
רש"י: ותירס - זו פרס: למה פירש כך?
גור אריה: מפני שמדי הוזכרו כאן ובכתוב נראה שפרס ומדי הם משורש אחד.