Principal English Translation:
you are one of our group; one of us; we are in some way equals
Horacio Carochi / English:
titèhuān(tin) = expression of solidarity
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), 513.
Attestations from sources in English:
Ti added has this effect. No other pronoun but we is used like this.
titehua yu mexica = We are one with the Mexica.
Robert Haskett and Stephanie Wood's notes from Nahuatl sessions with James Lockhart and subsequent research.