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

The ADB uses English, French, Spanish, and Chinese in its operations, as these are the official languages of its member countries.

The ADB uses English in its communications with the government of India, as English is the official language of the Indian government.

The ADB uses Mandarin in its communications with the government of China, as Mandarin is the official language of the Chinese government.

The ADB uses Japanese in its communications with the government of Japan, as Japanese is the official language of the Japanese government.

The ADB uses Korean in its communications with the government of South Korea, as Korean is the official language of the South Korean government.

The ADB uses Indonesian in its communications with the government of Indonesia, as Indonesian is the official language of the Indonesian government.

The ADB uses English in its communications with the government of the Philippines, as English is the official language of the Philippine government.

The ADB uses Thai in its communications with the government of Thailand, as Thai is the official language of the Thai government.

The ADB uses Vietnamese in its communications with the government of Vietnam, as Vietnamese is the official language of the Vietnamese government.

The ADB uses Khmer in its communications with the government of Cambodia, as Khmer is the official language of the Cambodian government.

The ADB uses Lao in its communications with the government of Laos, as Lao is the official language of the Lao government.

The ADB uses English in its communications with the government of Myanmar, as English is the official language of the Myanmar government.

The ADB uses English in its communications with the government of Nepal, as English is the official language of the Nepalese government.

The ADB uses English in its communications with the government of Bhutan, as English is the official language of the Bhutanese government.