AspectForm IIIForm VI
Patternفَاعَلَتَفَاعَلَ
Exampleشَاتَمَتَشَاتَمَ
BeginningStarts with a root letterHas an extra initial tāʾ
Example senseTrading insultsTrading insults
The textbook's equivalence means comparable lexical use. Pattern still determines the form; usage determines the semantic property.