Principal English Translation: 

to go; to go along (well or badly), mainly seen in the 3rd person
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), 242.

Orthographic Variants: 
Alonso de Molina: 

yauh. ni. (pret. onia.) yr a alguna parte.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 31v. col. 1. Thanks to Joe Campbell for providing the transcription.

Horacio Carochi / English: 

yauh = to go
Horacio Carochi, S.J., Grammar of the Mexican language with an explanation of its adverbs (1645), translated and edited with commentary by James Lockhart, UCLA Latin American Studies Volume 89 (Stanford: Stanford University Press, UCLA Latin American Center Publications, 2001), 515, and see 118-19, 150 n1, 158-63, 166-67, 167-68 n2, 170-71, 290-91, 254-55, 292-93, 382-83 (especially n3)

Lockhart’s Nahuatl as Written: 

ni. to go, leave. present. pl. huih. irregular verb with roots ya/yā and hui. pret. ōniyah. imperfect nihui(y)a. future niyāz. 242
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), 242.

Attestations from sources in English: 

niauh = I go
tiauh = you go
yauh = he/she/it goes
tihui (variant tiyahuih found in some places = we go
anhui (anyahuih ditto) = you all go
hui (yahuih ditto) = they go

niaz = I will go
tiaz = you will go
yaz = he/she/it will go
tiazqueh = we will go
anyaqueh = you all will go
yazqueh = they will go

yahqui (preterit of yauh, and -qui is an archaic form)
huiloa (impersonal of yauh)
hui (supplicative form of yauh, has to be plural, see Carochi)
Rebecca Horn's notes from Nahuatl classes with James Lockhart. Card file in possession of Stephanie Wood.

amoqui ma tia Canpahícoyaía = Ahmo:quimatia ca:mpa i:c o:ya:ia = They did not know thereby where they went
Anónimo mexicano, ed. Richley H. Crapo and Bonnie Glass-Coffin (Logan, UT: Utah State University Press, 2005), 41.

ma tiquintlapocan ma huiyan = Let us release them; let them go
Codex Chimalpahin: Society and Politics in Mexico Tenochtitlan, Tlatelolco, Culhuacan, and Other Nahuatl Altepetl in Central Mexico; The Nahuatl and Spanish Annals and Accounts Collected and Recorded by don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, eds. and transl. Arthur J. O. Anderson and Susan Schroeder (Norman: University of Oklahoma Press, 1997), vol. 2, 52–53.

auh noxocoyouh, campa in tiyauh? campa in titztiuh? = Well my youngest child, where are you going? Where are you headed? (Mexico City, 1649)
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), 204.

oya = went (preterite) (sometimes split like this: o ya)
huia = went (imperfect)
huallauh = to come forward; to come back, return; to bring back
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.

ohualeuh or ohualehuaya = came from
Mapa de Iztacapan, associated with El Cardonal, Hidalgo, Mexico; see the Wired Humanities Project's Mapas Project, http://whp.wired-humanities.org/mapas/Iztacapan/index.shtml (write [email protected] for passwords), folio 5r.

hualyaque tlahtoque huiya Caxtillan = the rulers who had gone to Spain came back
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 170–171.ic mitoaia onacoqujxtilo in quauhtecatl, iehica ca iaomjquj, ixco iauh, ixcopa itztiuh, ixco monoltitoc in tonatiuh, qujtoznequj, amo mictlan iauh = This was called “the sending upward of the eagle man”: because he who died in war went into the presence of [the sun]: he went before and rested in the presence of the sun. That is, he did not go to the land of the dead. (16th century, Mexico City)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 2—The Ceremonies, No. 14, Part III, 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, 1951), 48.

Attestations from sources in Spanish: 

Yaque Caxtilan = Fueron a Castilla (Tlaxcala, 1662–1692)
Juan Buenaventura Zapata y Mendoza, Historia cronológica de la Noble Ciudad de Tlaxcala, transcripción paleográfica, traducción, presentación y notas por Luis Reyes García y Andrea Martínez Baracs (Tlaxcala y México: Universidad Autónoma de Tlaxcala, Secretaría de Extensión Universitaria y Difusión Cultural, y Centro de Investigaciones y Estudios Superiores en Antropología Social, 1995), 174–175.

in tiaz = te has de yr
tleipampa tiauh = porque te vas
Pedro de Arenas, Vocabulario Manual de las Lenguas Castellana, y Mexicana (Mexico: Henrico Martínez, 1611), 12.

niauh = yo voy; tu, tiauh, él/ella, yauh; nosotros, tihuili; vosotros, anhuih; ellos, huih; niaya (pretérito imperfecto), yo iua, yo iba; onia (pretérito perfecto) = yo fui; oniaca (pretérito plusq.) = yo hauia ydo, yo habia ido; nihuia = yo yua, yo iba, fui, auia ydo, habia ido; niaz (futuro) = yo yre, yo iré; tu, tiaz; él/ella, yaz; maniauh (imperativo) = vaya yo; tu, ma xiauh; él/ella maiauh; nosotros, matiuian; vosotros, maxiuian; huiloa (impersonal, presente) = todos van; huiloac (impersonal, pretérito) (Tetzcoco, 1595)
Antonio del Rincón, Arte mexicana, 33, reproducida digitalmente por el Internet Archive, http://archive.org/stream/artemexicana00rincrich/artemexicana00rincrich_....

Hora que chisnacas para nias = Y ahora ¿Qué me das para que vaya?(s. XX)
Fernando Horcasitas, "La Danza de los Tecuanes," Estudios de Cultura Náhuatl 14 (1980), 239–286, see especially pp. 260–261.

IDIEZ morfema: 
IDIEZ traduc. inglés: 
See YĀ.
IDIEZ def. náhuatl: 
Xiquitta YĀ.
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