Why does it say "Kol Eleh Bnei Yaktan"?
Radak (Bereishis 10:29): No one else mentioned had 13 sons.
Malbim: All these were his own sons. "Mitzrayim Yalad Es Ludim v'Es Anamim", i.e. these nations came from his sons and grandsons 1 .
What is the source that they were not Mitzrayim's sons? Malbim did not bring "Bnei Shem? Utz v'Chul" (even though the Torah says that they were Shem's grandsons), for there it does not say Yalad. (PF)
Why did Yaktan merit to have so many sons?
Rashi (Bereishis 10:25): He was Maktin himself (diminished his esteem).
'Rashi': He used to minimize his affairs.
Rashi (Bereishis 10:25): writes that Yaktan was Maktin himself. How did his father Ever know to call him Yaktan?
'Rashi': Ever was a great Navi. We do not expound other names, for they were not given via a Navi.
