Why does the word tear have different pronunciations?

Why? Different meanings of the Word came from different roots.

There are a couple of different meanings to this Word:

Tear (t-air, an "e" sound): Verb, meaning to rip (past tense "tore"), or a noun, meaning the rip itself. E.g. "I want to tear a hole in this paper"; "There is a tear in the paper".

Tear (t-ear, an "i" sound then r): Noun, meaning what is cried. E.g. "I cried tears this morning. An entire bucket of them." or "Tears don't fall, they crash around me" (Alexisonfire lyric).