Normally we say Basmala when we start reciting from the starting of a Surah. If we start reciting from the middle of a Surah, then only the Ta'awwudh is said.
When we read a book in English, usually we read it in our minds, without moving our tongue and lips. But for the recitation of the Qur'an, it is important to recite using the mouth, the tongue and lips must be moved. Otherwise the recitation is not counted and one does not get rewarded for it.
So when you come across an Ayah (in Arabic) written in an English book, and you want to recite it, then it is always recommended to say the Ta'awwudh.