The map is much more detailed and up-to-date than an earlier map published by Soustelle (1937), in which the Sierra Ñähñu were only part of a larger map of all Otomí and Pamé speakers. The "hole" between Zacualpan and Tlachichilco is primarily a region of Spanish-speaking cattle ranchers in the higher regions of Veracruz. Conflicts between the ranchers and Indians reached violent levels in the 1990s. One can see a southwest to northeast extension of culture due to the hill-valley configuration of this region. The high mountains between these valleys have evidently inhibited the spread of culture. Today one can find considerable dialect and cultural differences between the Ñähñu of Texcatepec and those of San Bartolo, separated from it by several mountains and valleys.