  Augustine's assertions and remarks, even though they do not offer a completely uniform concept of sign, were fundamental to the development of medieval semiotic, and they constituted the only elaborate theory of signs until the 13th century (apart from the original theory of Peter Abelard). In his incomplete early work, De Dialectica, Augustine massively draws on the terminology of the Stoic philosophy of language, though in many points fundamentally modifying its sense.[4]  It is especially in the concept of sign where his difference from Stoic doctrines becomes apparent. For according to the most refined theory of Stoic logicians, a sign in the proper technical sense (semeion) was seen as the abstract propositional content of a sentence insofar it is functioning as the antecedent in a true implication by means of which a hitherto unknown truth is revealed. By contrast, Augustine is favoring a reifying concept of sign. A sign, as he defines it in line with the descriptions given by Cicero and the Latin tradition of  rhetoric,[5]  is “something that shows itself to the senses and something other than itself to the mind” (Signum est quod se ipsum sensui et praeter se aliquid animo ostendit) (Augustine De dial. 1975, 86). The concept of sign, thus defined in terms of a triadic relation (a sign is always a sign of something to some mind), provides the general basis for Augustine's theory of language: “To speak is to give a sign in articulate voice” (Loqui est articulata voce signum dare) (Augustine De dial. 1975, 86). Speech, in further contrast to Stoic semantics, is essentially characterized by its communicative function. A word, by definition, is a “sign of something, which can be understood by the hearer when pronounced by the speaker” (uniuscuiusque rei signum, quod ab audiente possit intelligi, a loquente prolatum) (Augustine De dial. 1975, 86). The communicative function[6]  is thus essential to the linguistic sign: “There is no reason for signifying, i.e., for giving signs except to convey into another's mind what the sign-giver has in his own mind” (Nec ulla causa est nobis significandi, id est signi dandi, nisi ad … traiciendum in alterius animum id quod animo gerit qui signum dat) (Augustine De doctr. chr. II 3, 1963, 34: 17–20). In his dialogue De Magistro (On the Teacher), however, written shortly after De Dialectica, Augustine denies that words or signs have the power of ‘showing’ anything in the sense of making something present to the understanding (Non … mihi rem, quam significat, ostendit verbum…) (Augustine De magistro X 32, 1974, 191). For this reason, still influenced by the tenets of the skeptical tradition at that  time,[7]  Augustine was limiting the capacity of the sign to its admonitory or commemorative function (Augustine De magistro XI 36, 1974, 194).