eloquent

expressing yourself readily, clearly, effectively

Having the power of expressing strong emotions or forcible arguments in an elevated, impassioned, and effective manner; as, an eloquent orator or preacher.

Latin 'eloquens', speaking

“This was by no means his idea of a man's duty in tribulation, about which he could be strenuously eloquent.”

— George Meredith, Complete Project Gutenberg Works of George Meredith

“The debate ended with an eloquent speech by Prime Minister Manuel Azaña pleading for the unanimity of the house "to condemn and exclude D.”