I believe this is largely an “American” thing.
Between about 1800 and 1900 several waves of immigration occurred from various parts of Europe. As each group came to a given city they formed their own “community” based on church, language, culture etc. The Church allowed for this and in many cases there were parishes established along ethnic lines very lose and even overlapping each other.
In my own family history, my mother lived on a street just a few blocks from two Catholic churches. Sts Peter and Paul were about 7 blocks one way and Sacred Heart was about 5 blocks the other way. Sts P&P was the German Catholic Church and Sacred Heart was the Irish Catholic Church. Because my mom’s family was of German heritage, they went to Sts P&P even though SH was closer.
Obviously the differing cultural backgrounds of the parishes would result in very different “flavors” in each parish, but as far as teachings go they would be the same.
Hope this helps.
Peace
James