If few letters have ‘silent letters’ in them, why have them in the first place?

This is the evolution of language.

LIGHT used to be said /li-ch (like a cat’s hiss) -/t

Liccchhhht.

So as the language developed the cchhhh sound disappeared but the /gh/ stayed.

Spanish is well-rid of silent letters except in ‘borrowed’ words from other languages.

When an orthography is made for an unwritten language, the orthographists (spelling-deciders) avoid ‘silent letters’ and a newly written language (usually a tribal or indigenous) is easy to ‘read’ (with or without understanding). English was written down centuries – nay millenia ago.

French has LOTS of silent letters too.

I have an issue with the person below me, because spanish do have a silent letter. The letter is “H” such as in “Historia” it should be pronounced “istoria” with out the “H” sound!

SO HA! YAY!