How did a city change when many people moved to it?

the answer is sociological. people from different countries came together with many different traditions and religions. these different people could barely understand each other however humans have the innate ability to learn and interpret things which means, through time they began to understand one another. sociologically, their traditions began being shared through communication and they were molded together to form an entirely new culture and set traditions. there are some however that separate which brings up china town and such and the expansion of cities.

as in size, people migrated from different areas and stayed in the same general area they arrived in. this in turn called for a need for food and other services so people who had trade opened up shop and surplused...

it all depends on the city