The Mexica, Acolhua, Tepaneca, Xochimilca, Chalca, etc are all various subgroups of the broader Nahua culture. By most accounts, they migrated into Central Mexico, primarily around what's Mexico city and the surronding valleys today, throughout the 13th and 14th centuries AD; transitoning from Aridoamerican nomadism and into Mesoamerican urban statehood, eventually coalescing into the Aztec empire after a series of wars and successon disputes under the control of a triple alliance of Tenochtitlan, Texcoco, and Tlacopan, which were inhabated primarily by Mexica(ns), Acolhuans,and Tepanecans respectively.
However, you don't really hear about this level of discerete subcultural/ethnic groupings for other Mesoamerican cultures, or at least not that i've encountered. The Mixtec are just the Mixtec, the Zapotec are just the Zapotec, same for the Purepecha, Totonacs, Huastecs, Tlapanec, Otomi and I don't even know the cultural status of the groups in central mexico but not belonging to the Nahuas or Otomi, such as whatever culture Cholula, Huextozinco, or Xochicalco; or the various states of West Mexico (other then the Purepecha Empire) like Jalisco or Colmia.
The only exception to this are the Maya, who seem to, relative to the Nahua, Mixtec, Zapotec, etc; seem to even be more culturally diverse and a higher-level label, being it's own 30-lanuggae large language tree, vs Nahuatl being a single language in the Uto-Aztecan tree, or Zapotec and Mixtec being single languages in the Oto-Manguean tree.
This begs the question what the "cultural taxonomy" of Mesoamerica is like. I have many questions, but i'm going to split them up into 3 main groupings:
Are Mexica, Acolhua, etc really more subgroups, or are they more discrete cultures like Mixtec vs Zapotec? What about the Mexica's subgroups of the Tlatoloca and Tenochca? If Tenochtitlan hadn't conquered and absorbed Tlatelolca, would they be treated as distinct like the Acolhua and Tepaneca. I imagine not since there were multiple cities belonging to each, but still. That also begs the question of what the political connotations of those groupings were: I've seen Texcoco described as the "Acolhua captial"; so were all the Acolhua cities under the domionon of Texcoco? Were each group politically aligned?
In regards to the Maya, where do they fit into this? What are the major Maya cultural subdivisons? I know I've heard lowland vs highland; or Kiche vs Itza vs Chontal, but I don't know any actual information about them. Would it be accurate to say that those divisions are more "taxonomically" comparable to Mixtec, Zapotec, or Nahua rather then "Maya" itself is, as if those were all genuses but Maya is a Family? It defdinetely seems something like that, considering the aformentioned nature of Maya linguistics and that the Maya compose an absolutely huge proportion of Mesoamerica geographically, across the entire Yucatan peninsula, which is like 1/3 of Mesoamerica.
This/these tie into the last point of 2, but I see Mesoamerica often split up into quadrants: the Yucatan/East/The Maya, the Gulf Coast, Oaxaca/Guerero, the West, and then the Center. Are these actually appropriate cultural subdivisions? If so, then "Maya" would indeed be a much more expansive label then just Nahua or Mixtec. I also see "central Mexico" mentioned a lot in a way that to me implies less the center of quadrants, as above, but more the entire central 1/3 of Mesoamerica, as opposed to Western Mexico and the Yucatan/the Maya. This also, to me, seems to be somewhat on point in terms of art motifs: Nahua and Mixtec art seems to share a lot of motifs and design traits, much moreso then Nahua or Mixtec vs Maya Is THAT division into 1/3's along the East-West appropriate? Do gulf coast cultures, central mexican ones, and Oaxaca/Guerrero ones share as much with each other as the various maya groups or West Mexican cultures? I will say that while Nahua and Mixtec art seems very, very similar, their art is noticably different from the Gulf Coast.
I realize i'm asking a lot here, I don't expect every reply to address every part of my post here, but even just answering indivual subquestions would be helpful. Thanks!
Sorry for the late response, but I am just coming back from doing fieldwork and I could not find time before to write a response to your very interesting set of questions.
First, I feel like one of the reasons why groups like the Nahua or Mayas are more widely recognized as having broader cultural diversities is because there has been far more research done in these parts than in other regional areas of Mesoamerica. To give you an example close to my area of expertise, while there are roughly 8 geographical regions in which the area of Oaxaca is subdivided, that are inhabited by at least 16-17 (depending on how you divide/subdivide languages) distinctive languages groups, you only hear about the Zapotecs and Mixtecs because most of the research is concentrated on those cultural areas. While each language family may in fact have its on historical development, it is obfuscated by the fact that little to no research has been done to illuminate said history. Thus, research in Mesoamerica is still concentrated very heavily in Central Mexico and the Maya area, while researchers in other parts have to find relevancy by appealing to connections with any of the two major regions.
However, this is not to say that such situation is merely a modern coincidence. In fact, I would argue that probably even the own Colonial administration relay heavily on those regions to begin with. For example, the Viceroy of New Spain was centered around Mexico City, and therefore more bureaucracy took place on this area which created a valley of Mexico-centric view, that in turn gave history a momentum of understanding the history of Mesoamerica through the lens of the valley of Mexico. To give a concrete example, one of the earliest chronologies created for Mesoamerica had three occupational periods: Teotihuacan-Toltec-Aztec. If you notice these three suppose occupational levels originate close to or in the valley of Mexico. Thus, if your starting point to understand Mesoamerica is the valley of Mexico, then other cultural regions would fall short of your measuring stick.
Related to my previous point, another reason why we know more about these regions, is because there were more documents written about them, or at least studied from these regions, than from any others. For example, you can find published versions of many books titled Chilam Balam, which oftentimes contain detailed pre-conquest and post-conquest accounts of local Maya histories. However, for many reasons, it is very hard to find published versions of the relaciones geograficas or the lienzos from small towns around the valley of Oaxaca. This creates a perceived situation where more local history is known about small Maya towns, than an entire area like the Chontal or Huave region of the isthmus of Tehuantepec.
Going back to my area of expertise, Oaxaca, the Mixtec area is actually subdivided into three regions: the Mixteca Alta, Mixteca Baja, and Mixteca de la Costa. But even these large subregions are not enough no encompass the actual diversity going on in each on those subregions. For example, in the Mixteca Alta, when we talk about the Mixtecs, we are for the most part talking about the polities that centered around the Valley of Nochixtlan: Yanhuitlan, Yucuita, Tilantongo, Teposcolula, Etlatongo, Pueblo Viejo de Nochixtlan, Jaltepec, among a few others. However, to say that all those polities are Mixtecs is very misleading because they never had any kind of pan-Mixtec identity that unified them. In fact, the rulers of Tilantongo had more affinities with the ruling house of Zaachila, in the valley of Oaxaca, than with those of Yanhuitlan. Furthermore, to call all of that area Mixtec, leaves behind the Chocho, Triqui and Tacuate polities that were living in what we called the Mixtec area. The problem arises because we make the mistake of equating related but distinct categories like community, polity, language, and identity; we want each of these categories to have easily identifiable and timeless boundaries, but most of the time they are more complex, intertwined, and socially embedded and ever changing meaning.