The best time to advocate for your program is when everything is going well. Here are a variety of ideas to market your program and let your stakeholders (students, parents, administrators, school committee, district community) know about the wonderful events, accomplishments and progress of your program.
If your program is at risk, here are a variety of ideas and plans to advocate for protecting or maintaining your program or part of your program.
Finally, check this out if you need research to demonstrate the benefits of language learning.