You'd have to define "major". English is the official, or main language spoken, in many countries including Australia, UK, US, New Zealand (with Maori), Canada (with French) and Ireland (with Irish Gaelic). It is one of several official languages in other countries including India, Kenya, Nigeria and Malaysia. English is used in some countries because there are too many local languages and to use one of them as "the official language" would possibly cause insult to speakers of other languages. In the case of Papua New Guinea a form of English called Tok Pisin is used because there are hundreds of languages and dialects.