An applicable example of the spread of ideas throughout history would be most notably during the renaissance and the enlightenment which spread scientific and artistic ideas with the assistance of literature, salons, and the like as well as the industrial revolution which allowed for faster travel and thus the intermingling of cultures. This led to what is widely regarded as "western culture" which is still seen today, because while countries in europe and the areas they colonized differed in some ways these periods allowed for fashion, government, art, and even education styles to become more standardized throughout regions.
Another example could be the spice trade across the silk road. The bolstered trade between countries, though far apart, created a cultural connection between the two which stimulated the spread of ideas throughout countries.
An example of similar linguistic intermingling would be within ancient Egypt. The we are able to understand hieroglyphics because of the base language used in the area which was used farther north and as the language evolved there were adaptations of it throughout the region. One such surviving adaptation, even though it was affected by the dialect of neighboring regions and the simplification of pronunciation allowed experts a glimpse into the likely translation of hieroglyphs (it was difficult because they only include the consonant of letters and no vowels and thus must be supplemented by the reader instead and without knowing the language in the form it was at the time it was written was difficult and the intercultural adaptations provided a way for the language to evolve while maintaining its roots)
The true answer to this question is that there is no one answer. There are plentiful examples of this throughout history because of the way societies evolve, intermingle, and fall even in ancient times. It mainly comes down to the strength of global trade, types of communication, and the location of settlements. It can also be affected by politics like war because any interaction between countries can affect their culture, customs, or relationship with one another. Basically you could come up with hundreds of examples in many different contexts. You might actually do some research on it and you might find some interesting historical tidbits and find an answer to the question that actual interests you.
