Comment by nkrisc

> English is one of few languages where the relationship between the writing and the pronunciation of the vowels is mostly unpredictable, so knowing whether a word is spelled with "o" or with "ou" does not help you to know how to pronounce it.

That is true, but it's a trade-off made for other benefits. Why is there a silent "g" in "sign"? Because it provides semantic meaning - it preserves its connection to works like signatory, signature, significant, signal, etc. While English spelling doesn't always help you pronounce the word, it does help you identify its meaning. If it was spelled "sine" or "sin" (if you choose to also do away with silent "e"s in your spelling reform) that connection would be weakened or lost.

Also, this has a lot to do with the pronunciation of words changing over time and drifting out of sync with the spelling, but the spelling not changing to match the new pronunciation in order to preserve the aforementioned connection with similar words.

I don't know if the "g" in "sign" was pronounced at some point, but other silent letters today exist because the Norman scribes used them to indicate sounds that were in fact pronounced by the Anglo-Saxons at the time, such as the oft-maligned "ough" - a sound which has pretty much entirely disappeared from modern English (but as I understand can still be found in an extant distant relative: Dutch).