The words hear, here sound the same but have different meanings and spellings. Why do hear, here sound the same even though they are completely different words?
The answer is simple: hear, here are homophones of the English language.
To perceive (sound) by the ear: Can you hear the signal?
To learn by hearing; be told by others: I heard she got married.
To listen to attentively: Hear what I have to tell you.
To listen to in an official, professional, or formal capacity: heard the last witness in the afternoon.
At or in this place: Stop here for a rest.
At this time; now: We'll adjourn the meeting here and discuss remaining issues after lunch.
At or on this point, detail, or item: Here I must disagree.
In the present life or condition.
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").