The words clabbered, clapboard sound the same but have different meanings and spellings. Why do clabbered, clapboard sound the same even though they are completely different words?
The answer is simple: clabbered, clapboard are homophones of the English language.
Simple past tense and past participle of clabber.
A long narrow board with one edge thicker than the other, overlapped horizontally to cover the outer walls of frame structures. Also called weatherboard.
To cover with clapboards.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, 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.