What recent technological development has had the greatest impact on human communication?

Communication related technologies have the greatest impact on human communication.
The advancement in technology has been exceptionally fast in the 20th and 21st century. Social media has a huge impact on how we communicate these days.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.