Mode-relations in language learning by language-deficient retarded subjects.

The relationship between language comprehension and production was examined with two severely language-deficient retarded subjects who were taught the plural form /z/. Comprehension and production were trained concurrently with different words in each mode until correct plural use occurred in the untrained mode for each word. Subsequent training of reversed plural use in comprehension for one subject and production for the other failed to result in reversed plural use in the untrained modes for those words. This mode-independence contrasted with interdependence displayed by normal children in earlier study using similar procedures. The results are discussed in relation to the normal developmental process and the possible deviation from it.