Complex sentence: Centuries later they themselves were replaced by the Pipil people, Nahua speaking groups who migrated from Mexico in the centuries before the European conquest and occupied the central and western regions, the Pipil were the last indigenous people to arrive in El Salvador.
Split into simpler sentences: Centuries later they themselves were replaced by the Pipil people, Nahua speaking groups who migrated from Mexico in the centuries before the European conquest and occupied the central and western regions. The Pipil were the last indigenous people to arrive in El Salvador.