Pure Falsetto has these characteristics:
Once one starts being able to change pitches and use a vowel other than [oo], then there is coordination with the arytenoid system.
Further, due to the crico-thyroid muscle system being close to and “friends” with the muscles of swallowing, the falsetto has a tendency to constrict and must be taught to function without engaging swallowing muscles. This is done by allowing and encouraging excessive air flow for a limited time. This breathy or pure falsetto exercised in conjunction with chest voice begins to transform into a falsetto that is singable.