The words craft, kraft sound the same but have different meanings and spellings. Why do craft, kraft sound the same even though they are completely different words?
The answer is simple: craft, kraft are homophones of the English language.
Skill in doing or making something, as in the arts; proficiency. See Synonyms at art1.
Skill in evasion or deception; guile.
An occupation or trade requiring manual dexterity or skilled artistry.
The membership of such an occupation or trade; guild.
A tough, usually brown paper made from wood pulp treated with a solution of sodium sulfate, used chiefly for bags and wrapping paper.
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").