The
Nahuan or
Aztecan languages are those languages of the
Uto-Aztecan language family that have undergone a
sound change, known as
Whorf's Law, that changed an original *t to before *a. Subsequently, some Nahuan languages have changed this to or back to , but it can still be seen that the language went through a stage. The best known Nahuan language is
Nahuatl.