What are the 15 languages written on back of 100Rs note?

There are 17 languages written on the back of a 100 rupee note, not 15.

Here are the languages:

1. Hindi: "भारतीय रिज़र्व बैंक" (Bharatiya Reserve Bank)

2. English: "Reserve Bank of India"

3. Assamese: "ভাৰতীয় ৰিজাৰ্ভ বেংক" (Bharatiya Rijarb Bank)

4. Bengali: "ভারতীয় রিজার্ভ ব্যাংক" (Bharatiya Rijarb Bank)

5. Gujarati: "ભારતીય રિઝર્વ બેંક" (Bharatiya Rijarb Bank)

6. Kannada: "ಭಾರತೀಯ ರಿಸರ್ವ್ ಬ್ಯಾಂಕ್" (Bharatiya Risarv Bank)

7. Kashmiri: "भारतीय रिज़र्व बैंक" (Bharatiya Rijarb Bank)

8. Konkani: "भारतीय रिज़र्व बैंक" (Bharatiya Rijarb Bank)

9. Maithili: "भारतीय रिज़र्व बैंक" (Bharatiya Rijarb Bank)

10. Malayalam: "ഭാരതീയ റിസർവ് ബാങ്ക്" (Bharatiya Risarv Bank)

11. Marathi: "भारतीय रिझर्व बँक" (Bharatiya Rijarb Bank)

12. Manipuri: "ভারতীয় ৰিজাৰ্ভ বেংক" (Bharatiya Rijarb Bank)

13. Nepali: "भारतीय रिज़र्व बैंक" (Bharatiya Rijarb Bank)

14. Odia: "ଭାରତୀୟ ରିଜର୍ଭ ବ୍ୟାଙ୍କ" (Bharatiya Rijarb Bank)

15. Punjabi: "ਭਾਰਤੀ ਰਿਜ਼ਰਵ ਬੈਂਕ" (Bharatiya Rijarb Bank)

16. Sanskrit: "भारतीय रिज़र्व बैंक" (Bharatiya Rijarb Bank)

17. Tamil: "இந்திய ரிசர்வ் வங்கி" (Indiya Risarv Vanki)

18. Telugu: "భారతీయ రిజర్వ్ బ్యాంక్" (Bharatiya Rijarv Bank)

19. Urdu: "بانکِ ِرِزَرْوِ ِہند" (Bank-e Rijarv-e Hind)

Let me know if you want more details on any of these languages!