Wrong! The peoples you talk about were all Latins speaking a variant of old Roman Latin. The non Latin speaking people were the Etruscan’s which Rome promptly set about conquering. The Roman was initially very exclusive-see Cato the Elder and the Greek ambassadors. Diversity is linked to the loss of Republican freedom with the rise of Imperial slavery and finally collapse.
Wrong! "Republican freedom" meant three dozen families ruling everyone else, 40 percent of the population in slavery (it was about 3:1 in Rome itself), and the decades conquests of neighboring groups led to the evolution of a permanent executive branch, non-Romans in the Senate (no more taxation without representation), and despite the best efforts of leaders as far back as Augustus, a serious decline in the inbred former aristocracy, with opportunity and upward mobility for citizens of the empire.