This approach is not a solution to anything. The 18:82 ratio needs to be addressed, which basically means starting to build interest in high school. Duolingo (etc.) would be better served by sponsoring interest groups and clubs in high schools, offering scholarships to graduating high school seniors, offering internships to high school students, etc. They need to market high tech careers to those high school girls who have the interest and proclivity for tech, but not the exposure that helps them realize it.