English is the official language of the ADB, as stated in its Charter.

Chinese is the most widely spoken language in the ADB's member countries, with over 1.3 billion speakers.

Hindi is the second most widely spoken language in the ADB's member countries, with over 500 million speakers.

English is the third most widely spoken language in the ADB's member countries, with over 300 million speakers.

Japanese is the fourth most widely spoken language in the ADB's member countries, with over 120 million speakers.

Korean is the fifth most widely spoken language in the ADB's member countries, with over 75 million speakers.

Indonesian is the sixth most widely spoken language in the ADB's member countries, with over 200 million speakers.

Tagalog is the seventh most widely spoken language in the ADB's member countries, with over 100 million speakers.

Vietnamese is the eighth most widely spoken language in the ADB's member countries, with over 90 million speakers.

Thai is the ninth most widely spoken language in the ADB's member countries, with over 60 million speakers.

Burmese is the tenth most widely spoken language in the ADB's member countries, with over 50 million speakers.

Khmer is the eleventh most widely spoken language in the ADB's member countries, with over 15 million speakers.

Lao is the twelfth most widely spoken language in the ADB's member countries, with over 10 million speakers.

Nepali is the thirteenth most widely spoken language in the ADB's member countries, with over 10 million speakers.

Sinhala is the fourteenth most widely spoken language in the ADB's member countries, with over 10 million speakers.