First-- Not Intern Rhumba.-- It is Intern. Latin.
The frame and posture in latin , can go thru various changes during the course of a given dance .
Its like comparing apples to oranges-- both fruit== both from a tree-- but different flavors .
Amer. style " rhythm ", has many similarities ( and many things identical ) to Intern Latin . The techniques, sometimes, take different paths .
The most obvious examples, are the commencement of Cha. And Rhumba ( in bronze ) is still Square ( the way we USED to dance it )
have done several dissertations on the authenticity of the Latin genre .Its posted on-- salsa forums -- also some postings on -- dance forums .
These will give you a much better understanding , about the development of the dances we " choose " to include in our social and competitive arena .