tlathui.

Headword: 
tlathui.
Principal English Translation: 

for the dawn to come
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 238.

IPAspelling: 
tɬɑtwi
Frances Karttunen: 

TLATHUI to dawn, to get light / amanacer (C) M has this bound with YE ‘already’ with the same meaning. See TLATHUĪTIĀ.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 296.

Lockhart’s Nahuatl as Written: 

Class 1: ōtlathuic. tla-, ithui variant intransitive counterpart of itta, so that the original meaning was for things to be seen.
James Lockhart, Nahuatl as Written: Lessons in Older Written Nahuatl, with Copious Examples and Texts (Stanford: Stanford University Press and UCLA Latin American Studies, 2001), 238.

Attestations from sources in English: 

tlathui (verb) = to dawn, to become light
Daniel Garrison Brinton, Ancient Nahuatl Poetry: Containing the Nahuatl Text of XXVII Ancient Mexican Poems (1877), 165.

Auh in ie iuhqui, in omestin õmomamaiauhque tleco, in icoac ie otlatlaque: niman ic quichistimotecaque in teteu, in campa ic quiçaquiuh nanaoatzin, in achto onuetz tleco: inic tonaz, inic tlathuiz. = And after this, when both had cast themselves into the flames, when they had already burned, then the gods sat waiting [to see] where Nanauatzin would come to rise-- he who first fell into the fire-- in order that he night shine [as the sun]; in order that dawn might break. (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 7 -- The Sun, Moon, and Stars, and the Binding of the Venus, No. 14, Part VIII, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 6.

cujx tonaz: tlathujz = Perhaps he will cause the sun to shine, to dawn (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 6 -- Rhetoric and Moral Philosophy, No. 14, Part 7, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1961), 189.

Attestations from sources in Spanish: 

auh in otlahuic = Pero, al amanecer (Mexico City, c. 1572)
Ana Rita Valero de García Lascuráin and Rafael Tena, Códice Cozcatzin (México: Instituto Nacional de Antropología e Historia, Benemérita Universidad Autónoma de Puebla, 1994), 103.

themes: 
Celestial Phenomena
Time, Calendar, Frequency