I would rather speak 10 languages because I can save more animals by convincing people in their language to stop hurting them.
I would want to speak, Indonesian or Malaysian because the maximum carnage is happening there for palm oil
The languages I want to speak are:
1. Arabic: A lot of poor north African cultures butcher animals for the Chinese market.
2. Indonesian, Malaysian
3. Korean, for the North Koreans to stop hunting Siberian tigers
4. Japanese, so they stop hunting whales.
5. Chinese, so they can be convinced that Rhino horn is actually hair and thus has no medicinal value in boosting virility.