The words step, steppe sound the same but have different meanings and spellings. Why do step, steppe sound the same even though they are completely different words?
The answer is simple: step, steppe are homophones of the English language.
The single complete movement of raising one foot and putting it down in another spot, as in walking.
A manner of walking; a particular gait.
A fixed rhythm or pace, as in marching: keep step.
The sound of a footstep.
A vast semiarid grass-covered plain, as found in southeast Europe, Siberia, and central North America.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.