Acquired is due to an identifiable cause (e.g., trauma, brain bleed, head injury, etc). Developmental is inborn and there is no identifiable cause to the aphasia.
on-line medical journal note: different types of dyslexia can be found in aphasia, especially inchildren (http://www.nidcd.nih.gov/health/voice/aphasia.htm)
A developmental disability is a disability the person is usually born with, whereas an acquired one could happen at some point in their lives, maybe by an accident or illness.
Both dysarthria and aphasia are abnormalities of speech. The chain of speech and abnormalities are as follow:
i. Hearing
ii. Understanding -- Aphasia
iii. Thought & word finding --...