Entrepreneur and engineer, Didier has created its first company in 1992, ONDIM, a B2B French pioneer of virtual and augmented reality. Since created L&J in 2007, he has focused L&J's activity on the B2C business model by promoting vocal technology on smartphones, and developing embedded artificial intelligence use cases.

Software engineer, Jean-Michel created his first video game at 13 and has served as the technical director of many companies. Pioneer of the Internet and voice over IP in the early 2000s (ISDNet, Cable&Wireless, B3G Telecom), he is the architect of L&J's proprietary technology since 2012.

With 40 years of experience teaching children from 3 to 10 years old, Nathalie is a teacher who has always sought the best tools to help her with her teaching. With doubleYou Kids she participated in defining Math 8's educative contents by organizing "Leon workshops" in different classes of her primary school.

Mike has been copyediting and teaching English to students of all ages for over five years. He has overseen the translations of Math 8's educational content and replicas of Leon’s voice interactions with kids. Originally from the United States, Mike helps to ensure that the English versions of doubleYou Kids apps are seamlessly adapted for native English speakers.