The Latin term infans, derived from the Greek phèmi ("I speak"), means "one who does not (or rather, not yet) speak," and refers to the baby before the acquisition of speech that marks the entry into childhood.

A number of authors (notably Melanie Klein and Donald Winnicott) used the term to describe those whose mode of communication is situated at a preverbal level. In the work of Jacques Lacan the term infans took on a further dimension in his discussion of language and its relation to the unconscious. Piera Aulagnier elaborated a theory of the mother-infant relation in terms of discourse (with the mother as "word-bearer"). The discussion here will be limited to the specific reference to language implied in the notion of infans.

In French translations of authors like Klein or Winnicott, terms such as bébé (baby), nourrisson (nursling), petit enfant (small/young child),...