What sign languages show

The chapter presents analysis of the motion properties of the environment that humans use to parse natural scenes, and the kinematics of articulator (hand) motion in American and Croatian Sign Languages, asking whether the kinematic distinctions between linguistic categories in sign languages are important to phonological and syntactic systems in sign languages. Based on motion capture and neuroimaging data from native signers and sign-naïve non-signers, we propose that sign languages grammaticalize perceptual features already available from the human visual system for the phonology-syntax interface.