This document discusses principles and methods of translation. It begins with Catford's definition of translation as replacing textual material in one language with equivalent material in another. It discusses issues like translation equivalence, types of translation like semantic and communicative translation, and structural elements like situational features, semantic structure, and levels of word meaning. It also examines sentence structure in English and implications for translation, including theme, subject types, and notions of structure across languages. Finally, it briefly discusses language varieties such as dialects, registers, styles, and modes that impact translation.