+ven through research in sign language is a special ! eld of language
research it has contributed 9ith ne9 kno9ledge about human lan;
guage because of the visuospatial nature. =he article introduces to
different issues in sign language research from a cognitive and neu;
ropsychological vie9. =hese issues are sign language linguistic> sign
aphasia> the neural organi?ation of sign language> signed short;term
memory> and the study of speech errors in sign language. =he overall
purpose of the article is to e@amine the structure and organi?ation of
sign language in comparison to oral language. Ahat linguistic> neu;
ral and cognitive similarities and differences are there bet9een sig;
ned and oral languagesB =he article demonstrates that the linguistic>
cognitive and neural basis for signed languages overall is similar to
oral languages. =he similarity of signed and oral languages indicates
an amodal cognitive organi?ation of human language.