The phrase "a speaker at a" is correct and usable in written English.
It can be used when referring to someone who is giving a talk or presentation at a specific event or location.
Example: "She was invited to be a speaker at a prestigious conference on climate change."
Alternatives: "a presenter at a" or "a lecturer at a".
He was a speaker at a conference of monks in Bangkok.
"Vilna is not simply a city, it is an idea," said a speaker at a Yiddish conference in 1930.
In October, 2011, Bob was a speaker at a conference organized by anti-racist groups in London.
"What America wants is to dismantle the Arab world," declared a speaker at a year-after forum in Cairo.Damascus radio talks of plans to "recolonise" the region.
It was a significant departure in tone for a speaker at a Romney campaign event, which generally feature measured critiques of his political opponents.
He was praised by a speaker at a parade in Pittsburgh for kissing his wife "in front of millions of people" at the Democratic National Convention.
"Billy Elliot" begins with postwar footage of a speaker at an annual coal miners' gala invoking "this new adventure" of nationalization and "the great experiment of socialism".
Antiwar protests have also become an accepted part of American history and culture, said Seymour Melman, emeritus professor of industrial engineering at Columbia University and a speaker at an antiwar protest on Wall Street in 1970.
A speaker at an event like Games Invest might sound a high note of ambition (such as following blue-ocean strategies or lean-startup thinking), but in practise they tend to be terrified of risk.
Everything we recorded came out of a speaker at one end and into a microphone at the other.
Rabbi Weinreb, who has a doctorate in psychology, was a speaker at the Nov. 5 Yeshiva University conference.
