Complex sentence: The process has not substantially declined in usage in the Mesoamerican region, though there has been a decline in North America and many North American Native American tribes, such as the Huron, no longer use the process.
Split into simpler sentences: The process has not substantially declined in usage in the Mesoamerican region, though there has been a decline in North America. Many North American Native American tribes, such as the Huron, no longer use the process.