Firstly, what is a 'native speaker' of any language?
In some countries such as Kenya, India, and various East Asian countries, "mother language" or "native language" is used to indicate the language of one'sethnic group, in both common and journalistic parlance (e.g. "I have no apologies for not learning my mother tongue"), rather than one's first language. Also in Singapore, "mother tongue" refers to the language of one's ethnic group regardless of actual proficiency, while the "first language" refers to the English language that was established on the island through British colonisation, which is the lingua franca for most post-independence Singaporeans due to its use as the language of instruction in government schools and as a working language.
One can have two or more native languages, thus being a native bilingual or indeed multilingual. The order in which these languages are learned is not necessarily the order of proficiency. Other examples are India, Malaysia and South Africa, where most people speak more than one language.
First language - Wikipedia, the free encyclopedia
Here's an interesting on-line discussion:
How would you define "native speaker of english"?
And here's a more academic study:
The second-largest English-speaking country is India:
Is India or US the biggest English-speaking country? | Antimoon Forum
List of countries by English-speaking population - Wikipedia, the free encyclopedia
The rapid growth of India's economy towards the end of the 20th century led to large-scale population migration between regions of the Indian subcontinent and the establishment of English as a common lingua franca between those speaking diverse mother tongues.
Indian English - Wikipedia, the free encyclopedia
And as such, Indians not only speak excellent English:
"An English-speaking Indian has native-like intuition in English, unlike a Chinese for whom English is assembled by a more academic thought process. For an Indian, English is more like an adjunct native language. We do some of our thinking in our Indian language and other things in English — that is, we have a native competence that spans two or more languages. No wonder we do so well in Toefl."
Indians beat English at their language - Times Of India
But it is replacing 'local' languages:
In Bangalore and elsewhere in Big City India, factors like great mobility, a demanding school system and mixed marriages are churning up a startling consequence: a generation of urban children is growing up largely monolingual — speaking, thinking and dreaming only in English.
“How do we define Ahana’s mother tongue?” asks Mr. Nagaraj. He speaks Kannada with his mother; his wife speaks Bengali with hers. Both grandmothers live nearby and attempt to converse with Ahana in their respective tongues. But she responds only in English.
It is an issue that at once cheers and distresses an entire band of middle-class Indians.
On the one hand, English has opened the doors to great job mobility in the past decade and much economic success. In a country of so many varied languages, English is the only linguistic commonality. Yet as the language increasingly becomes the de facto mother tongue in urban families, many are dismayed at the trend, contending that its rampant use will strip them of their sense of Indian-ness.
“English is unifying us with the rest of the world but alienating us from our familial and cultural roots,” says Mr. Nagaraj, who still turns to Kannada metaphors when he needs to drive home a point.India's New 'English Only' Generation - NYTimes.com
English is an official language in most former British colonies:
List of countries where English is an official language - Wikipedia, the free encyclopedia
But not in Malaysia:
The official language of Malaysia is Malaysian, a standardised form of the Malay language. Historically English was the de facto administrative language, with Malay becoming predominant after the 1969 race riots. English remains an active second language, and serves as the medium of instruction for maths and sciences in all public schools. Malaysian English, also known as Malaysian Standard English, is a form of English derived from British English.
Malaysia - Wikipedia, the free encyclopedia
And it should not be confused with the 'Anglosphere' which some see as a rather romantic, backward-looking anti-European notion:
Anglosphere - Wikipedia, the free encyclopedia
English has been chosen often for political reasons:
Nigeria has one of the biggest collection of languages in the world (if not THE biggest), and they use English as the national language, because it's neutral to all the other ones (and it's used as a to boot). Some people though have English as a native language in the country.
Can a Nigerian be classified as a Native English speaker? - Yahoo! Answers
Nigerian English - definition and examples of Nigerian English
But it's often a question of education and class:
The official language of Nigeria, English, the former colonial language, was chosen to facilitate the cultural and linguistic unity of the country. English, however, remains an exclusive preserve of the country's urban elite, and is not widely spoken in rural areas, which comprise three quarters of the countries population.
Languages of Nigeria - Wikipedia, the free encyclopedia
This can often have racist overtones:
Native English speakers who are of Asian descent or candidates with Asian looks will NOT be consideredNative English speakers (Caucasians ONLY) from the UK, USA, Australia, New Zealand and Canada need apply
Who is a native speaker of English?- eChinacities Answers | answers.echinacities.com
This paper argues that the English Language Teaching (ELT) industryoften does not treat all speakers of English as equal in its hiring practices.Rather, it gives preferential treatment to White native speakers of English.