Complex sentence: However, the linguists who studied Genie firmly believed she could not be retarded; they pointed to Genie's progress on several scales measuring estimated mental age, which all indicated developmental gains far larger and more rapid than would be expected from someone whose retardation was congenital.
Split into simpler sentences: However, the linguists who studied Genie firmly believed she could not be retarded. They pointed to Genie's progress on several scales measuring estimated mental age, which all indicated developmental gains far larger and more rapid than would be expected from someone whose retardation was congenital.