Who first distinguished between creeping trotting and galloping inflation?

The distinction between creeping, trotting, and galloping inflation was first popularized by economist Milton Friedman. In his analysis, he categorized inflation based on its rate and impact on the economy, with creeping inflation being low and manageable, trotting inflation being moderate, and galloping inflation representing high and destabilizing rates. Friedman's work in the mid-20th century helped to shape the understanding of inflation dynamics in economic theory.