Cuadro Descriptivo y Comparativo de las Lenguas Indígenas de México

2 vols. 8vo. Description, analysis and comparison of the various indigenous languages. Among them: the Mixteco, the Mamé, the Otomí, the Cahíta, the Zapotec, the Tarasco, the Maya, the Cora, the Comanche, the Tejano, etc. Pimentel claimed to be "the first to present a scientific classification of the indigenous Mexican languages ​​based on comparative philology." He proposed several families that were accurate (as well as some that were not that accurate). First edition of this important work on the classification of the native languages of Mexican Indians.