Language mastery has a fundamental role in science, engineering and technology, both in the learning stage and throughout professional practices. The present chapter focuses mostly on the roles of language in engineering and technology, spanning through a variety of relevant aspects, from the optimisation of language usage in reports and article writing to historical synopses about crucial issues such as the relationships between language and logic and between language and knowledge. It thus comprises practically implementable outlines, practically-oriented motivations for the need of high level language mastery, and theoretical motivations through the awareness of the role of language as a crucial focus of philosophical and epistemological investigation throughout centuries.