 Lockhart's analysis of Nahuatl as an index of cultural change relies on Molina's 1555 "Vocabulary", which translates Nahuatl ("Mexicana") to Spanish ("Castellana"), as a key source for loanwords from Spanish into Nahuatl in which he calls Stage 2, the second generation of language contact (ca.1550 to 1600).Molina records many nouns from Spanish that became integrated into Nahuatl, but his dictionary also records Nahuatl descriptions of Spanish concepts or objects.