The words reading, reeding sound the same but have different meanings and spellings. Why do reading, reeding sound the same even though they are completely different words?
The answer is simple: reading, reeding are homophones of the English language.
The act or activity of one that reads.
The act or practice of rendering aloud written or printed matter: skilled at forensic reading.
An official or public recitation of written material: the reading of a will; a reading by the poet of her own works.
The specific form of a particular passage in a text: an unusual reading of the old manuscript.
Architecture A convex decorative molding having parallel strips resembling thin reeds.
Parallel grooves cut into the edge of a coin at right angles to the faces.
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.