I’m confused. The modern word in french is “reçu”, which is pronounced something like “ruhsue”. The English word is “receipt” but pronounced something like “ruhseet”. There’s no “ooh” sound in the original Latin, so it’s not just a matter of adding extra or silent letters in there, it’s a complete change to the vowel sounds, plus the re-addition of a ‘t’ sound.
I oversimplified a bit! Sorry!
Words always shift over time and borders. The words “recu” and “receive/receipt” are pretty close and used to be closer. To be more accurate it was “receite” when they adopted it from French. Compared to Latin “recepta” which has a hard P in it. So adding “P” from Latin to the spelling as “receipt” but leaving the pronunciation as Anglo-French “receite” was the most silly part.
Well, English is always silly with the various silent letters. The worst are the silent letters that nonetheless change the pronunciation of the non-silent letters nearby.
Like, I saw a place today named “something-valu”, with no “e” on the end. With no “e” it should really be pronounced “valoo”. Adding the “e” somehow changes it to “valyoo”. Rather than changing the vowel sound, it adds a consonant-like /j/ sound (IPA) to the start of that syllable.