The words emerged, immerged sound the same but have different meanings and spellings. Why do emerged, immerged sound the same even though they are completely different words?
The answer is simple: emerged, immerged are homophones of the English language.
Simple past tense and past participle of emerge..
To submerge or disappear in or as if in a liquid.
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.
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").