The words cubical, cubicle sound the same but have different meanings and spellings. Why do cubical, cubicle sound the same even though they are completely different words?
The answer is simple: cubical, cubicle are homophones of the English language.
shaped like a cube
Of or pertaining to a <xref>cube</xref>; <xref>cubic</xref>.
Of or pertaining to a cube.
small room in which a monk or nun lives
small area set off by walls for special use
small individual study area in a library
A small enclosure in a public <xref>toilet</xref> for individual use.
Definitions from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved., from Wiktionary, Creative Commons Attribution/Share-Alike License., from The Century Dictionary. and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.