Indirect speech is a remarkable trait of human communication. The present paper tackles the sociobiological underpinnings of communicative indirectness discussing both socio-interactional and cognitive rationales behind its manifestation in discourse. From a social perspective, the use of indirect forms in interactions can be regarded as an adaptive response to the epistemic implications of transacted new information in small primary groups, representing – in Givón’s terms – our “bio-cultural” descent. The design features of indirect strategies today may therefore be explained in (...) terms of a form-function mapping in which indirect communicative expressions allowed a “safer” transaction of contents and a more cooperative attitude of speakers in both face-to-face and public contexts of communication. The unchallengeability effects notably induced by underencoded meanings have now received extensive experimental backing, unveiling intriguing underlying cognitive mechanisms such as the well-known cognitive illusions or fallacies. (shrink)