ihiyotl.

Headword: 
ihiyotl.
Principal English Translation: 

breath, respiration; life; sustenance (see Karttunen), blown air, a puff of air, a blast of air (see Molina)

Orthographic Variants: 
ihiotl, iiotl
IPAspelling: 
ihiːyoːtɬ
Alonso de Molina: 

ihiotl. aliento huelgo, o soplo.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 36v. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

IHĪYŌ-TL breath, respiration, hence one’s life, sustenance / aliento huelgo, soplo (M) In T and Z the second vowel has been absorbed into the following Y, reducing the stem by a syllable to (I)HYŌ. This is a reduplicated form that implies an unattested *ĪYŌ-TL or an unattested verb *IHĪ ‘to breath’ ultimately from Ī ‘to take a breath,’ but Ī exists as a verb in Nahuatl with the sense ‘to drink.’ IHĪYŌ-TL appears to be related to EHĒCA-TL ‘wind,’ which in some dialects of Nahuatl even has A in the first two syllables . The long vowel of the second syllable of IHĪYŌ-TL is abundantly attested in C.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 98.

Attestations from sources in English: 

ihiyotl tlatolli, "breath + words = fine speech;"
See Sell's comments in Bartolomé de Alva, A Guide to Confession Large and Small in the Mexican Language, 1634, eds. Barry D. Sell and John Frederick Schwaller, with Lu Ann Homza (Norman: University of Oklahoma Press, 1999), 22.

one of the basic spiritual components of the human being, located in the liver (sixteenth century, central Mexico)
Justyna Olko, Turquoise Diadems and Staffs of Office: Elite Costume and Insignia of Power in Aztec and Early Colonial Mexico (Warsaw: Polish Society for Latin American Studies and Centre for Studies on the Classical Tradition, University of Warsaw, 2005), 175.

Ihiyo, itlatol = His breath, his words.
"This was said only about the words of kings. They said 'The king's venerable breath, his venerable words.' It was not said about anyone else's words, only 'the illustrious breath, the illustrious words of our lord.'"
A Scattering of Jades: Stories, Poems, and Prayers of the Aztecs, eds. Thelma Sullivan and T. J. Knab (1994), 208.

themes: 
Philosophy
Politics, Power, Governance
Social Hierarchy, Commoners, Elites
Speech, Speaking, Oral Tradition