"The Universe speaks in many languages, but only one voice. The language is not Narn, or Human, or Centauri, or Gaim, or Minbari." "It speaks in the language of hope. It speaks in the language of trust." "It speaks in the language of strength and the language of compassion. It is the language of the heart and the language of the soul. But always, it is the same voice. It's the voice of our ancestors speaking through us and the voice of our inheritors waiting to be born. It is the small still voice that says we are one. No matter the blood, no matter the skin, no matter the world, no matter the star, we are one. No matter the pain, no matter the darkness, no matter the loss, no matter the fear, we are one. Here gathered together in common cause, we agree to recognize this singular truth and this singular rule. That we must be kind to one another." "Because each voice enriches us and ennobles us and each voice loss diminishes us. We are the voice of the universe. The soul of creation. The fire that will light the way to a better future. We are one." "We are one"
- G'Kar's Declaration of Principles
The following races are members of this alliance :
Humans, Minbari , Centauri , Narn , Drazi , Brakiri , Vree , Gaim , Enphili, Pak'Ma'Ra , Hyach, Abbai

The Humans didn't want to join the alliance at first, because they feared a Minbari domination within the alliance. After Delenn promised to share Minbari technology with all other races, the Humans decided that it is better to be a part of the alliance. The Interstellar Alliance was the biggest union ever recorded in history, composed of about 150 races and 300 systems. Every race was allowed to join but they had to sign the Declaration of Principles. All members stay sovereign and the alliance acts like the "United Nations" back in the 20th Century.
During the first year, the alliance faced its first major threat. An unknown race began attacking member races and colonies. Later Ranger Lenier found out that the Drakh had undermined the Centauri Government and had started a war between the Centauri and the Interstellar Alliance. A fleet of Narn, Drazi and Brakiriforces went to Centauri Prime and laid large parts of the planet surface into ashes.
The Ranger and the WhiteStarfleet were the armed forces of the alliance but they had no right to interfere into the policy of a member race. The WhiteStar fleet patrols the borders of the member races and acts as a kind of "peace keeping force".

The following video provides you with the correct English pronunciation of the word "Army of Light - History (More...)", to help you become a better English speaker.