Display the World's Most Common Languages by Country 

Get a list of world countries.

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X countries = CountryData[];

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X Take[countries, 10]

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Get a list of each country's most common language.

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X firstLanguages = First[CountryData[#, "Languages"]] & /@ countries;

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X Take[firstLanguages, 10]

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Group the countries by language.

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X languagegroups = Map[First, GatherBy[Thread[countries -> firstLanguages], Last], {2}];

These are the countries in which Spanish is the most common language.

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X languagegroups[[8]]

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Color a world map by language group.

In[7]:=

X GeoListPlot[languagegroups]

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