The phrase "a speech on behalf" is correct and usable in written English.
It can be used when referring to delivering a speech as a representative of someone else or a group.
Example: "She delivered a speech on behalf of the entire team, expressing gratitude for the support received."
Alternatives: "a speech representing" or "a speech for".
9.10am: Paul Kenny, the GMB general secretary, delivers a speech on behalf of the TUC.
The caucuses operated by the Republicans are reasonably straight forward; after someone reads a speech on behalf of a candidate, people got outside and vote.
Cardinal Giovanni Battista Re, a longtime top Vatican official, delivered a speech on behalf of all the cardinals thanking the pope and urging him to stay the course.
Mr. Sinwar's status as a prison leader was apparent within hours of his release on Tuesday; he was invited to give a speech on behalf of the prisoners from a specially built stage in Gaza City.
Pete Townsend, of the Who, rammed Abbie Hoffman off the stage when Hoffman tried to interrupt the Who's performance to give a speech on behalf of John Sinclair, the jailed leader of the White Panther Party.
Known for her down-to-earth style of political communication, Dole was catapulted into national consciousness at the 1996 Republican National Convention when she gave a speech on behalf of her husband's presidential bid.
Instead, her father Mitch received it and made a speech on her behalf.
Kate Moss collected Bowie's prize and read a speech on his behalf urging Scottish voters to reject independence.
Her son Alexander Aris attended the ceremony in Oslo in her place, and made a speech on her behalf.
Mr. Kerry said he had been impressed by Mr. Reagan as early as 1964, when he was a Yale student and Mr. Reagan gave a televised speech on behalf of Barry Goldwater's candidacy.
She not only went, but delivered a vigorous speech on behalf of women's rights in a country that was well known for acting forcefully against them.
