SIL International serves language communities worldwide through research, translation, training and materials development. Their training includes linguistics, literacy and multilingual education, anthropology, translation, and language and culture.
Audio Forum has links to a wide selection of language courses from basic tourist introductions to courses by Foreign Service Institute to children's Bible stories in multiple languages.
The Institute of Strategic Languages and Cultures offers one-year intensive courses in Russian, Chinese, and Arabic. Students study not only the language, but also history and culture.
The Center for Intercultural Training offers a four-week course on second language acquisition with concurrent courses for children and teens.
Wheaton College in Wheaton, Illinois, offers online courses in second-language acquisition through their Institute for Cross-Cultural Training.
Culture Bound offers a variety of courses on culture and language acquisition for missionaries in several formats: online or on-site, self-directed, personal coaching, or cohort style
Mission Training International offers a four-week pre-field training course in Palmer Lake, CO, for adults, teens, and children. Their program includes practical skills, language learning skills, and preparation for personal vitality and healthy relationships.
BOOKS ON LANGUAGE ACQUISITION:
Language Acquisition Made Practical by E. Thomas Brewster and Elizabeth S. Brewster
Fluent Forever: How to Learn Any Language Fast and Never Forget It by Gabriel Wyner