Adsum

I am present.
Historical Examples

He heard the different voices—adsum, adsum—the roll was being called!
The Reign of Greed Jose Rizal

“adsum,” Frank answered, softly, and Katrine flashed a smile of appreciation back at him.
Katrine Elinor Macartney Lane

Once more it was France’s good fortune to be able to answer, adsum.
With Americans of Past and Present Days J. J. Jusserand

There he passed the remainder of his days, and there he said “adsum” when his name was called for the last time in this world.
The Story of the Upper Canada Rebellion, Volume 1 John Charles Dent

The one crucial call had come for him, and he could not answer “adsum.”
Robert Annys: Poor Priest Annie Nathan Meyer

Instead of answering “Here” or “adsum,” in the usual way, the boy whose name was called stood in his place and held up his hand.
Tom, Dick and Harry Talbot Baines Reed

adsum amicis, venio in senatum frequens ultroque affero res multum et diu cogitatas easque tueor animi, non corporis viribus.
Cato Maior de Senectute Marcus Tullius Cicero

sentence substitute
I am present