A spokesman or representative was an individual who made statements on behalf of a group or another individual.
In 2000 and 2001, Gerald Moss was a spokesman for the Millennium Gate project. (VOY: "11:59")
Ben Childress was the representative of the Rigel XII miners. (TOS: "Mudd's Women")
Captain Lindstrom was a Space Command representative who appeared at the court martial for James T. Kirk in 2267. (TOS: "Court Martial")
Ambassador Robert Fox was a representative of the United Federation of Planets, apparently, in fact, "a special representative." (TOS: "A Taste of Armageddon")
Kor named Baroner as representative of the Organian people, who was to act as the liaison between the Klingon Defense Force and the civilian population. (TOS: "Errand of Mercy")
In 2268, Lieutenant Nyota Uhura monitored the radio waves of the planet 892-IV. She heard the Roman Empire spokesman attempting to disparage the religion of the Children of the Son. However, he could not do so, for the Children were not worshipping the sun. They were worshipping the Son of God. (TOS: "Bread and Circuses")
A few years before 2368, Beverly Crusher met the Bajoran Jas Holza at a symposium. She found him to be a very concerned leader and a good spokesman for his people. (TNG: "Ensign Ro")
In 2367, in an illusory future created by Barash, William T. Riker was the key spokesman in securing an alliance between the Federation and the Romulan Star Empire. Riker had gained the trust of the Romulans after years of distrust and conflict by saving the crew of a Romulan battle cruiser. (TNG: "Future Imperfect")
In 2370, Quark was the spokesman for the Promenade Merchants' Association. When the Promenade was closed for longer than usual, Quark said he was going to file an official protest with Captain Benjamin Sisko. Sisko informed him to put it in writing. Quark left to get a PADD. (DS9: "Treachery, Faith and the Great River")
In 2375, Kurros was the spokesman for the Think Tank. (VOY: "Think Tank")