Indigenous peoples of Mexico
When Mexico gained independence in 1821, the casta system was eliminated as a legal structure, but racial divides remained. 
White Mexican argued about what the solution was to the "Indian Problem", that is indigenous who continued to live in communities and were not integrated politically or socially as citizens of the new republic. The Mexican constitution of 1824 has several articles pertaining to indigenous peoples. The second article of the constitution of Mexico recognizes and enforces the right of indigenous peoples and communities to self-determination and therefore their autonomy to:
History of Mexico
The fact that there was an existing prehispanic tradition of writing meant that when the Spanish friars taught Mexican Indians to write their own languages, particularly Nahuatl, an alphabetic tradition took hold. It was used in official documents for legal cases and other legal instruments. The formal use of native language documentation lasted until Mexican independence in 1821. Beginning in the late twentieth century, scholars have mined these native language documents for information about colonial-era economics, culture, and language. The New Philology is the current name for this particular branch of colonial-era Mesoamerican ethnohistory.