The story
Write comes from Old English wrītan. Its Germanic ancestor meant "to carve, to scratch", and its relatives show it: German ritzen means "to scratch, carve" and reißen "to tear". Early Germanic writing was runes cut into wood, bone or stone, so to "write" was, literally, to scratch.
The W was a real sound. Old English wrītan began with a lip- rounded W gliding straight into the R. Speakers kept it through the Middle Ages and then simplified the cluster: wr- was reduced to plain R, apparently during the 1600s — the same century the K fell silent in knee and know.
The vowel moved too. The ī of wrītan was a long "ee"; the Great Vowel Shift turned it into "eye". So write once sounded like "WREET", and today it is a homophone of right, rite and wright (as in playwright) — four spellings, one sound.
