Complex sentence: This neighborhood, northwest of the Loop, was first settled by Polish and Slovak immigrants, but with the rise of Ukrainian nationalism and the influx of political refugees during World War I, it assumed a Ukrainian cultural identity which lingers to this day.
Split into simpler sentences: This neighborhood, northwest of the Loop, was first settled by Polish and Slovak immigrants. With the rise of Ukrainian nationalism and the influx of political refugees during World War I, new residents gave it a Ukrainian cultural identity, which lingers to this day.