&gt;<i>Religion can and does preserve memes and linguistics, but only trade can scale it out.</i><p>If it was just for trade, language learning would be relegated to merchants in those countries and few others.<p>Government, bureaucracy and occupation matters more than trade in this regard. That&#x27;s how latin become the norm in a large area during the roman empire -- and not because everybody in those regions traded directly with Romans or couldn&#x27;t agree on pricing otherwise.<p>Same e.g. for French -- it&#x27;s not because of trade they got big as a language in the 18-early 20th centuries, but because the french run a big colonial empire.<p>And English, beyond trade, were the language of the big British colonial empire, and afterwards of the dominant culturally power that was America (Hollywood, rock, pop culture etc.).