“First language acquisition” commonly means the acquisition of a single language in childhood, regardless of the number of languages in a child’s natural environment. Language acquisition is variously viewed as predetermined, wondrous, a source of concern, and as developing through formal processes. “First language teaching” concerns schooling in the language that is intended to become the child’s first (or “main”) one. Mainstream teaching practices similarly take languages as formal objects, focusing on literacy skills, so-called phonological awareness, and other teaching about the language. This article gives a first overview of folk beliefs associated with language acquisition and teaching, highlighting whether and how they can guide applied linguists’ concerns about child language development and early pedagogical practices.