‘These are the sons of Shem after their families, after their tongues, in their lands, after their nations.'
Compare Genesis 10:5; Genesis 10:20. The descriptions confirms that ‘sons' is to be taken in the broader context of describing tribes, lands and nations.
The mention of language in each of these references is interesting. There is no attempt to divide by language. We must therefore see it as drawing attention to distinctions of language in preparation for the account given in Genesis 11.