 He explicitly distinguished two types of “language of action.” The first one is “natural” (and thus appears to correspond to the use of natural signs also described in the Essay). Its signs depend on the conformation of the organs (Treatise of Animals II. 4, Grammar I.1, Logic II.2). As a consequence, different species of animals have a different natural language insofar as they have different organs (Treatise of Animals II.4). This language is innate in its expression since different signs are naturally caused by different ideas independently of any learning. However, the interpretation of this language is not innate: we have to learn to interpret its signs (Grammar I.1, Logic II.2). (Strictly speaking, cries, facial expressions, and gestures are signs only insofar as we interpret them: before any interpretation they are just the effects on our body of some ideas occurring in our minds.) The second type of language of action is institutional or artificial. Condillac makes clear that its signs are artificial but they are not arbitrary (Grammar I.1). They are not arbitrary because they are chosen according to a rule of analogy with the natural signs (Grammar I.1, Logic II.2).