PewResearchCenter. Of the national identity attributes included in the Pew Research Center survey, language far and away is seen as the most critical to national identity. Majorities in each of the 14 countries polled say it is very important to speak the native language to be considered a true member of the nation.

Roughly eight-in-ten or more Dutch, British, Hungarians and Germans believe the ability to converse in their country’s language is very important to nationality. Canadians and Italians are the least likely to link language and national identity. Nevertheless, roughly six-in-ten in Canada and Italy still make that strong connection.
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Europeans see language as a strong requisite of national identity
The European Union has 24 official languages and a number of other regional and minority languages among its 28 member states. Majorities in all of 10 European nations surveyed say it is very important to be able to converse in the local tongue, ranging from 84% of the Dutch to 59% of Italians.

Although majorities agree on the link between language and national identity, older Europeans and those on the political right often feel more strongly about the importance of native language facility.

Read more: http://www.pewglobal.org/national-identity/