What is a native speaker of English?
Native speaker is actually not a technical term. Most people believe that a native speaker is someone who was raised from childhood, or from birth, speaking English, and that it is their mother tongue. People may be included in the category of native speaker if they are bilingual and speak both English and another language from birth. This is common in couples in which one parent is an English speaker and the other isn’t, or is a non-native English speaker.
A non-native speaker of English is someone who has learned English as an additional or second language, and doesn’t use it as their main language of communication at home or in their personal life.
Others argue that if you’ve spent the majority of your life in an English speaking environment, or that you were educated through English as a medium of instruction for most of your time in formal education, then you may be a native speaker. As you can see, there is no single ‘clear cut’ definition of what a native speaker actually is.