The words beach, beech sound the same but have different meanings and spellings. Why do beach, beech sound the same even though they are completely different words?
The answer is simple: beach, beech are homophones of the English language.
To leave stranded or helpless.
The shore of a body of water, especially when sandy or pebbly.
The sand or pebbles on a shore.
The zone above the water line at a shore of a body of water, marked by an accumulation of sand, stone, or gravel that has been deposited by the tide or waves.
A deciduous tree of the genus Fagus having smooth gray bark, alternate simple leaves, and three-angled nuts enclosed in prickly burs. The best-known species are F. grandifolia of eastern North America and the European species F. sylvatica and its numerous cultivated forms.
The wood of any of these trees, used for flooring, containers, plywood, and tool handles.
Any of several other woody plants, as in the genera Carpinus and Nothofagus.
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").