Imagine if you do a favour for the goddess Athena, and as a reward, she gives you a gift of five languages. You can learn to speak, read and write any five languages instantly, with proficiency equalling your current first language, and it doesn’t take away from your current language skills in any way. What five languages would you pick?

Since I already know Spanish, I'd probably go with Mandarin, Thai, Arabic, Latin, and Farsi. THough German is a strong contender as well.