Bilingual Hispanics ages 18-29 have unparalleled spending power and influence in America, which is why top marketers are scrambling to connect with them.

Thirty-eight percent of Hispanics in that age range are bilingual, a number that's risen over the past decade. Because of this, marketers don't known which language to use to best reach them, and they've been forced to investigate influences on bilingual millennials.

Bilingual speakers have a number of cognitive advantages over their monolingual peers, but the neurological impact of bilingualism on commercial advertisement hasn't been explored until now. Nielsen collaborated with Univision Communications Inc. and Starcom MediaVest Group's Multicultural Division to gauge the reactions to four ads, covering different categories that aired in both Spanish and English.

Nielsen's proprietary consumer neuroscience technology was used to measure the neurological effectiveness of identical or nearly identical advertisements in English and Spanish.

They found that the Spanish-language version of an consistently performed as well as or outperformed its English counterpart. No English ad performed significantly better than the same ad in Spanish. Overall, Spanish ads seemed to better reach bilingual millennials, particularly those that were emotional in nature and featured social interactions.

Spanish-language ads resonated better in regards to television programming and were more memorable and emotionally engaging when aired alongside Spanish programming than English ads within English programming. When viewers were "primed with Spanish programming, Spanglish ads were less engaging and therefore seemed less relevant."

Additionally, seeing two older women communicating was most emotionally engaging for young bilingual Hispanics, followed by the appearance of a product suite and an older woman; a young woman on a tablet and an older woman; a younger woman and an older woman; and a product demo with an older woman.

Research shows that switching between languages required increased focus, distracting from emotional engagement and memory. When made to adjust from one language to another, viewers' focus tended to shift away from content and toward language processing.

Additionally, the study revealed that key messaging and branding should not occur within 10 seconds of a language shift. Effectiveness and comprehension is lost during that time while transitioning between languages.

Millennials, who are natural translators, also find it redundant when advertisements translate messaging for bilingual millennials. Presenting info in English and Spanish appears redundant and viewers are likely to disengage.

It's imperative for marketers to understand the two fastest growing demographics, Hispanics and millennials, and learn how to optimize messaging. The study indicates that the use of language does, indeed, sway the financial decisions of bilingual Hispanic millennials, and advertising in Spanish can yield positive results for businesses looking to tap into this market.

Even so, language is important, but it isn't all that matters. Sounds and sights also play a role. When there's disconnection between audio and visual information for viewers, there is confusion. With English messaging, Spanish voiceovers seemed to suffer. When audio and visual information is out of sync, the ad is "harder to process and disengages the viewer." Also, familiar characters that are known for speaking English aren't as engaging when they appear speaking Spanish.

Hyundai, ESPN, Corona and Dish Network ran TV ads in Spanish and English during the World Cup targeting the multicultural millennial population. The campaigns included Latinos on screen, a nod to the fact that Latinos like seeing themselves represented in the general market, as well as in Spanish-speaking outlets.