matlapitza.

Headword: 
matlapitza.
Principal English Translation: 

to whistle (or make a whistling effect) with the hands and mouth (see Molina)

IPAspelling: 
mɑːtɬɑpiːtsɑ
Alonso de Molina: 

matlapitza. ni. (pret. onimatlapitz.) silvar con las manos y boca.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 53r. col. 2. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

MĀTLAPĪTZ(A) to make a whistle with the hands and mouth / silbar con las manos y boca (M) [(3)Tp. 165]. See MĀ(I)-TL, PITZ(A).

MĀTLAPĪCHILIĀ applic. MĀTLAPĪTZ(A)
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 139.

Attestations from sources in English: 

niman ye ic neacomanallo auh in goernador oc nen quihualito matlapitzallo niman ye ic netenhuiteco tlacahuaco = the people began to riot and the governor cried in vain, “Play music with flutes and wind instruments.”[sic] Then the people came out from the meeting yelling and beating their mouths.
Ezequiel G. Stear, Nahua Horizons: Writing, Persuasion, and Futurities in Colonial Mexico (Tucson: University of Arizona Press, 2025), 134–135, citing Anales de Juan Bautista, 1582, f. 25v.