phrase usage - What defines a native English Speaker?

I think this particular phrase creates a lot of concern in English learners. From general conversation to posts here, we see native speaker a common usage when talking about a person who speaks English by birth. So according to this definition, inhabitants of all the countries considered as English speaking countries should be considered as native speakers. But herein lies my confusion. Would we conclude a random inhabitant of these countries to be a native speaker (as there is a chance of them to be a English speaking person)?

Also, I think Native speaker can also be one whose mother tongue is not English but uses English a lot in day-to-day life. For example, I don't speak English by birth, but as India is a country full of diversities, I have to use English daily for at least 5 hours a day in my normal life. So can I consider myself as native because I use it frequently?

UPDATE 1 - From Googling, I could not find any dictionary sites explaining this phrase. The results only include different forum answers. So I thought of asking the question here and perhaps wise users here can help me out with the actual meaning.

UPDATE 2 - Later I thought it is worth adding that Anglo Indian families (and some purely Indian families too) who are born and raised here in India, speak English from birth and their first language is English and English is their primary means of communication although I cannot admit they fully abide by or understand all English cultural values like a British or an American. So what can I call them? Are they native?

Answer

I think we need to clarify a couple of definitions:

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  Native English speaker – A person whose first language is English (they learned English from birth or as a very young child), and for whom English is the primary means of communication.

  
  


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  Fluent English speaker – A person who learned English later in life (i.e. as an older child, teenager, or adult), and who is very proficient in both spoken and written English.

  
  

There is nothing wrong with not being a native English speaker, and many non-native speakers have far better English skills than myriads of native speakers.