Hispanic bilingual Millennials (Billennials) are an increasingly important consumer group. Defined by their ability to speak both English and Spanish, it is critical to understand the impact of language on advertising in order to optimize messaging for this demographic. In ground-breaking research, Nielsen, Univision and SMG did just that. Using consumer neuroscience technology, they explored how Billennials' brains reacted to advertising on a second-by-second basis to reveal consumers' unarticulated language preferences, and the impact of these preferences on how the ad was received. We will also show brain response in real-time by conducting a live demo of Nielsen's brand new Fourier One Headset.