How can a nation maintain its identity?

There are many aspects of a nation which separate it from other nations. An autonomous nation is one that stands on its own, has well defined borders and a raison d'etre..reason for being. To study any one particular nation thoroughly, you can research the regional geography of that country. To study one aspect of the nation, you can research the topic...perhaps you want to know about how people make a living in that country...ask an economic geographer and you will find how people make their livings all over the world. The same is true for political systems...political geographers will give you objective descriptions of political systems throughout the world.

A major way of maintaining identity is to have a national language. When countries start to move away from their primary language (i.e. become bi-lingual, tri-lingual) it begins a process of separating the individuals living in the country...and this fosters division and introduces centrifugal forces which may lead to internal implosion. Division and other centrifugal forces make countries susceptible to being conquered and losing their identities as autonomous nations. Just having a national language is not an assurance that a country will maintain its identity.

To answer this question honestly and thoroughly you must take a multi-disciplinarian approach. You can ask historians, economists, lawyers, political scientists and get many answers, but the more you ask, the more you will have information for yourself to decide. Geographers use this method to fully understand world problems, etc. That's why I suggested approaching geographical sources for the best answers.

Some nations maintain identity be being isolated from the rest of the world.

Hope this gets you started!