Spanish and, from there, were diffused into hundreds of other languages in the region. Most of these loanwords denote things indigenous to central Mexico, which the Spanish heard mentioned for the first time by their Nahuatl names. English has also absorbed words of Nahuatl origin, including avocado, chayote, chili, chipotle, chocolate, atlatl, coyote, peyote, axolotl and tomato. Classification As a language label, the term Nahuatl encompasses a group of closely related languages or divergent dialects within the Nahuan branch of the Uto-Aztecan language family. The Mexican Instituto Nacional de Lenguas Indígenas (National Institute of Indigenous Languages) recognizes 30 individual varieties within the "language group" labeled Nahuatl. The Ethnologue recognizes 28 varieties with separate ISO codes. Sometimes Nahuatl is also applied to the Pipil language (Nawat) of El Salvador and Nicaragua. Regardless of whether Nahuatl is considered to refer to a dialect continuum or a group of separate languages, the varieties form a single branch within the Uto-Aztecan family, descended from a single Proto-Nahuan language. Within Mexico, the question of whether to consider individual varieties to be languages or dialects of a single language is highly political. In the past, the branch of Uto-Aztecan to which Nahuatl belongs has been called Aztecan. From the 1990s onward, the alternative designation Nahuan has been frequently used instead, especially in Spanish-language publications. The Nahuan (Aztecan) branch of Uto-Aztecan is widely accepted as having two divisions: General Aztec and Pochutec. General Aztec encompasses the Nahuatl and Pipil languages. Pochutec is a scantily attested language, which became extinct in the 20th century, and which Campbell and Langacker classify as being outside general Aztec. Other researchers have argued that Pochutec should be considered a divergent variant of the western periphery. Nahuatl denotes at least Classical Nahuatl, together with related modern languages spoken in Mexico. The inclusion of Pipil in this group is debated among linguists. Lyle classified Pipil as separate from the Nahuatl branch within general Aztecan, whereas dialectologists such as Una Canger, Karen Dakin, Yolanda Lastra, and Terrence Kaufman have preferred to include Pipil within the General Aztecan branch, citing close historical ties with the eastern peripheral dialects of General Aztec. Current subclassification of Nahuatl rests on research by , and . Canger introduced the scheme of a Central grouping and two Peripheral groups, and Lastra confirmed this notion, differing in some details. demonstrated a basic split between Eastern and Western branches of Nahuan, considered to