The word "COFFA" is spelled with two "F"s because it is derived from the Old English word "cofa" which meant "chamber" or "room". In IPA phonetic transcription, the word is written as /ˈkɒfə/. The first sound is a short "o" followed by a "f" and a schwa sound. The final sound is another short "a". The spelling may seem unusual to some readers, but it is a reflection of the word's Old English roots.