Atla, which he lists as Totonac, is really Aztec.

The _presidente_, upon a local map, showed us the interesting way in which natural barriers limit idioms.

Two little streams, coming together at an acute angle, may divide three languages--one being spoken in the angle and one on either side.
In Tlaxco, a small village in this _municipio_, four idioms are spoken--Aztec, Otomi, Totonac and Tepehua.
Two years before, just as my work was ending, we were in the great Otomi town of Huixquilucan, in the state of Mexico.

While resting at midday, I noticed a neatly-dressed and clean young indian, plainly not Otomi, with whom I conversed.

He was an Aztec, and much interested in the work we were doing.