tlaca.

Headword: 
tlaca.
Principal English Translation: 

that is to say (see Karttunen); or, an interjection, oh yes! (see Lockhart)

IPAspelling: 
tɬɑkɑh
Frances Karttunen: 

TLACAH that is to say / asi (C), palabra del que cae en la cuenta y enmienda lo que dice (C) This is abundantly attested in C as a free form and also bound with the particles ZO and CEH < ZO (Y)EH, all used as interjections. It contrasts with TLĀCAH, the plural form of TLĀCA-TL ‘person’ and with TLĀHCAH, ‘at midday.’
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 251.

Horacio Carochi / English: 

tlacà = intejection, oh yes!
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.