Plato believed that thinking is simply covert talking. Max Müller, who defined humans as thinking creatures, agreed and consequently claimed that infants and deaf people are not human. Darwin, on the other hand, contends that animals and a fortiori infants have the power of forming general concepts and therefore possess at least some form of thinking. Today all the evidence supports Darwin's view, but the consequences of this fact still don't seem to be fully acknowledged in linguistics.
Looking back at the last half century of linguistic research one observes recently – after a period of focussing on submodules like syntax, morphology and phonology – a growing interest in the interfaces between these subsystems. The main thrust of this talk is to argue for multidisciplinary efforts in exploring also the external interfaces that connect language and the different implementations of this faculty with the other divisions of the human mind. One example is the interface of linguistic cognition with conceptual thought. Being prerequisites for decision making, concepts are essential for the survavival of mobile lifeforms. What activates the mental representation of a concept are primarily representations of their instances and secondarily activated representations of other concepts. Arguably, representations of linguistic signs are concept representation activators of a third kind, one that allows a controlled way of both intraindividual activation and cross-individual activation sharing.
Accordingly, language acquisition is viewed as the enrichment of pre-linguistic cognition with this new kind of concept activators (short for: concept representation activators). Similarly, language evolution is seen as building on a fairly differentiated non-linguistic cognitive equipment of primates. Conceiving language as a module that is well integrated into the non-linguistic domains of human cognition entails also an interest in precisely specifying the interactions between them after language has emerged. The repercussions of a specific language type on non-linguistic thinking have long been discussed under the name of Whorf effects. The great attractivity of this idea for laypersons may have bolstered Whorf scepticism among scientists. But since Lera Boroditsky and collaborators at Stanford University have demonstrated the influence of arbitrary gender assignment on association with sex-related features even in non-linguistic experiments, providing thus the arguably most convincing evidence for the reality of such effects, the object of scepticism has shifted from the existence to the strength of this influence. This gives additional support to the concept of language as a module of cognition that is integrated into a network of mutual dependencies.
Disentengling this network will probably require a well-organized meta-network of multidisciplinary efforts.