Esperanto is phonetically spelled -- one letter, one sound. Its root words are principally drawn from the world's largest language family, the Indo-European, thus imparting maximum familiarity to the maximum number of people. International words are fully utilized. Esperanto's grammatical rules are easy to learn, with no exceptions. Words are built by the systematic use of prefixes and suffixes. The Universal Esperanto Association has branch offices in 87 countries with more than 2,000 active teachers. Regular radio programmes are broadcast in Esperanto to a worldwide audience from stations in 10 countries.