Accurate non-word spelling despite congenital inability to speak: phoneme-grapheme conversion does not require subvocal articulation.

Previous work has shown that children with motor speech disorders (dysarthria) have no particular difficulty in spelling non-words containing sounds that they cannot produce accurately in their own speech. This suggests that subvocal articulation is not implicated in generating a graphemic representation from a phonological string. However, it could be argued that, although severely unintelligible, dysarthric individuals may be able to use their own articulation as a basis for translating between phonemes and graphemes. In this study we investigated spelling of words and non-words in cerebral palsied individuals, including speechless (anarthric) as well as dysarthric subjects. Although spelling abilities of these individuals were below control levels, there was no evidence that different processes were used, and one anarthric individual achieved perfect performance in spelling a list of non-words which included consonant clusters. It is concluded that spelling by the 'indirect' route can be achieved in the absence of any articulation.