Given a text, write a compressed version of it in a single sentence.

I have no quarrel with Renfrew's theory—notwithstanding the generally received wisdom that has placed the homeland north of the Black Sea region and the Volga steppes. It is difficult for the nonspecialist reader ( like me ) to assess the validity of his arguments, which are based on his contention that the language ( and its congeners ) were carried along by the spread of nomad pastoralism.
I have no quarrel with Renfrew's theory, but it is difficult for the nonspecialist reader to assess the validity of his arguments which are based on the fact that language was carried along by nomad pastoralism.