Conversation so far:
what is the difference between the northern vietnamese army and the vietcong
The North Vietnamese Army (NVA or PAVN) were the formal army of North Vietnam while the Viet Cong was the guerrilla Army of South Vietnam.
where did the phrase viet cong for the guerilla army originate
The phrase Viet Cong comes from the phrase cong san Viet Nam, meaning Vietnamese communist, and denotes only southerners who supported the communist cause.

Question: what are the origins of the group
Self-contained rewrite: what are the origins of the viet cong