Possible sequence of events, counting backward from age 16 or 17 could go like this:
1. Try out the immersion experiences at Concordialanguagevillages.org in Bemidji, MN
2. As a family, consider hosting a few weeks or months, or whole school year (next best thing to being an exchange student)
3. Try out more immersion summer camp (1, 2 or 4 weeks = a school year's worth of "contact hours" credit)
4. Research the exchange program choices: Rotary, AFS.org, YFU.org, or the NSLI-Y for Strategic Languages (they have a few choices to study inside the USA for those languages, too -mainly Chinese, I think).
5. Get ready to go by researching the country, people, stories, movies, art and music, current events etc.
* depending on the young person's interest in people/languages you can choose the challenge-level (Spanish or French is closest to English)
The main thing about languages is motivation --discovering what it is you are seeking or attracted to.
When you know that, then no matter if you have a good or bad day, still you keep working on it.
And languages (your native one, or other ones you do) are essentially social glue - something you do with other people face to face, or in print and Web.
So after learning a set of words and phrases, then you start relating to people. And to get to the highest levels many people find that a strong friendship (pals or romantic) is the best motivator!
One great thing about the 21st century is the wealth of images, sound, movies and publications you can get.
Back in the 1980s satellite TV was the only way to get much content, and that was confined to college campuses.
So now a curious young person can dabble in lots of languages/lands before picking his top choices.
Rotary had a checklist of 45 countries and usually you can get one of your top 5, as an example.
Often there is financial support available. For example www.yfu-usa.org has a pretty extensive section devoted to full and partial scholarships.
Some places don't even get enough applicants to claim the money each year (e.g. Japan and Korea, I believe).
Rotary International Youth Exchange is special because you are "adopted" by the club - you live with 3 families usually during the year (but they have a 6 month and summer version, I think, too) and attend some of the weekly meetings. So you "officially" represent USA and become a lifelong alumnist. Former Rotary kids are a little bit like Eagle Scouts in a way.
Rosetta Stone has a sample chapter for 32 languages or something like that all on a single free disk.
A great visual sampler of world areas is the series of photo essay books by Peter Menzel and Faith D'Aluisio,
Material World (1994)
Women in the Material World (1996)
Hungry Planet (2004)
Man Eats Bug (2007?)
Each book follows a similar organization: visually show families in both "modern" and developing parts of the world.
Flipping through these pages gives an upclose perspective.
AFS Global Leaders Scholarships for students
AFS scholarship opportunities. Awards of $900-$5000 are available for students to participate in
AFS' international programs. http://www.afsusa.org/study-abroad/scholarships/global-leaders/
FLSAS / Foreign Language Study Abroad Service
http://www.flsas.com/ [subjects include the following]
Foreign Language Study Abroad Programs
Total Language Immersion Programs (4 options / 4 separate programs)
Foreign Language Institutes (Small Classes & Private Tutoring).
Special Programs for Teenagers & Pre-Teens (6 to 17 years).
Spanish in Miami (not quite study abroad)
HomeStay Only
Cultural & LifeStyle Immersion (2 options / 2 separate programs)
HomeStay Only Program for Adults or Children or Adults & Children Together
For those with or without language skills
HomeStay Only for Teens (Knowledge of the language of the country required.)