Cross-cultural evidence shows that the semantic domain of emotion words is organized along two dimensions: valence (pleasantness vs. unpleasantness) vs. arousal (low vs. high). However, collectivist cultures may bias their members to favor valence as valuable cues for interpreting social phenomena, whereas individualist cultures may bias their members to attend to somasthetic arousal to interpret intrapersonal states. This paper presents evidence that over generational time immigrant bilinguals from a collectivist culture (Mexico) to an individualist culture (the US) de-emphasize valence contrasts in the semantic domain of emotions in their first language (Spanish) and increase their emphasis on arousal contrasts. Thus, over generational time, the structure of first language emotion semantic space shifts in the direction of the majority culture.