Why do many words have silent letters when even without them the word would sound the same, like ‘island’ and many others.

Question

I tried asking my English teacher back in school but even she did not have an answer.

In: 157

Answer 1

As French silent letters and combination of letters to create a different is part of our daily life.
As exemple the sounds O can be written o, au, aux, eau, eaux and haut ( I may have missed others).
H is completly silent unless there is a C in front, then you prononce it Shh, the word chateau is pronounced shato
And if its a P in front then its pronounced F, phénomène is pronounced Fénomène, its the same meaning as in english

We got plenty of similar situations, It could be simplier but it would ruin the culture around French (thats just my take)