The words tailer, tailor sound the same but have different meanings and spellings. Why do tailer, tailor sound the same even though they are completely different words?
The answer is simple: tailer, tailor are homophones of the English language.
One that makes, repairs, and alters garments such as suits, coats, and dresses.
To make (a garment), especially to specific requirements or measurements.
To fit or provide (a person) with clothes made to that person's measurements.
To make, alter, or adapt for a particular end or purpose: a speech that was tailored to an audience of business leaders.
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.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").