Have you considered teaching Esperanto as a first foreign language?
Here's some reasons why you might:
1. You might not have a foreign language to offer*
2. You might not have time (Esperanto is designed for quick mastery so takes 6 times less time than most European languages and 22 times less time than Mandarin or Japanese).
3. You might want to encourage interest in, and communication with, children in dozens of different cultures.
4. You might want to leave the choice of language identity to the child, when s/he is old enough to choose.
5. Success breeds success- subsequent languages are easier and more likely when you are already bilingual.
* "Talking to the Whole Wide World" is designed for monolingual teachers. At the end of about 100 hours of games, songs and learning everyone knows Esperanto.