According to experts, na_hua-tl means ‘someone who makes an agreeable sound, someone who speaks my language’.
na_huatlahto_l-li means ‘the Náhuatl language’, and
na_huatla_cah (plural) means the Náhuatl-speaking nation.
The root *na_hua- appears to mean ‘audible’, ‘intelligible’, ‘clear’.
Frances Kartunnen, author of An Analytical Dictionary of Nahuatl, explains: "The use of the word Náhuatl as a language name and the term Nahuah as an ethnic term have been mined out of old sources, but I am not sure they were much used in precontact [pre-Hispanic] time.
"Nahuatlahtolli - ‘clear, intelligible speech’ - was contrasted with popoloca - ‘to speak gibberish.’ So the Mesoamerican world could be divided into ‘us’ and ‘them’ in terms of ‘people whose language is mutually intelligible with ours’ and ‘people whose language is unintelligible.’"
To put it crudely, the Aztecs thought their language was the only decent one (so they made it the language of their empire) and all other languages were rubbish!
With thanks to Anthony Appleyard and Frances Kartunnen via the Nahuat-l forum.
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