Architecture of Human Language from the Perspective of a Case of Childhood Aphasia — Landau–Kleffner Syndrome


  • Koji Hoshi Keio University
  • Kyoko Miyazato Hakuoh University


critical period, dual-stream model of speech processing, electroencephalographic (EEG) abnormalities, Landau–Kleffner syndrome (LKS), transcranial direct current stimulation (tDCS)


This paper addresses Landau–Kleffner syndrome (LKS), a childhood aphasia, from the perspective of I-language and the critical period for first language acquisition. LKS involves a language disorder and behavioral disturbances resembling autistic spectrum disorders due to electroencephalographic abnormalities with continuous spike-and-waves during sleep over the temporal regions. Comparing LKS with other childhood syndromes, the architecture of language is explored through elucidating the linguistic mechanisms behind the language disorder in LKS on the basis of Hickok & Poeppel’s (2007) dual-stream model of speech processing. It is claimed that early onset LKS provides further support for the critical period for first language acquisition and modularity of mind (the faculty of language), and that verbal auditory input during the critical period is most crucial for language recovery and development in LKS. Considering that electroencephalographic abnormalities affect cognitive/motor functions, ameliorating neural dysfunction in the affected brain areas with proper application of trans-cranial direct current stimulation is recommended.

Author Biography

Koji Hoshi, Keio University

Department of Economics Professor