Editing Expressive aphasia (section)

===Manual language and aphasia===
In deaf patients who use manual language (such as [[American Sign Language]]), damage to the left hemisphere of the brain leads to disruptions in their signing ability.<ref name="sciencedirect.com"/> [[Paraphasia|Paraphasic]] errors similar to spoken language have been observed; whereas in spoken language a phonemic substitution would occur (e.g. "tagle" instead of "table"), in ASL case studies errors in movement, hand position, and morphology have been noted. Agrammatism, or the lack of grammatical morphemes in sentence production, has also been observed in lifelong users of ASL who have left hemisphere damage. The lack of [[syntactic]] accuracy shows that the errors in signing are not due to damage to the motor cortex, but rather area manifestation of the damage to the language-producing area of the brain. Similar symptoms have been seen in a patient with left hemisphere damage whose first language was [[British Sign Language]],<ref name="ReferenceA">{{cite journal|last1=Marshall|first1=Jane|title=Aphasia in a user of British Sign Language: Dissociation between sign and gesture|journal=Cognitive Neuropsychology|date=15 June 2004|volume=21|issue=5|pages=537–554|doi=10.1080/02643290342000249|pmid=21038221|s2cid=27849117}}</ref> further showing that damage to the left hemisphere primarily hinders linguistic ability, not motor ability. In contrast, patients who have damage to non-linguistic areas on the left hemisphere have been shown to be fluent in signing, but are unable to comprehend written language.<ref name="sciencedirect.com"/>