Why are some letters silent in English....?

Why are some letters silent in English....?
 

why are some letters silent in English....? For example, In the word "walk", l is silent. Can someone tell me why...?

I'm no expert, but the general reason is that the English vowel length is extremely variable. With only 5 vowels (ignoring y) these are used to represent 14 (?) different sounds, so something has to be there to determine exactly which vowel is meant.

for example:

hat

That 'a' is short, there is no reason for it to be anything else.

hate

Here, the 'e' is there to express the fact that the 'a' is long. The 'e' is not pronounced.

Another mechanism is a double consonant:

bitter

The double 't' indicates that the 'i' is short

biter

With only one 't' the 'i' is long. The extra 't' in bitter is not pronounced.

As for walk, the vowel sound is somewhere between 'a' and 'o', and this is expressed by inserting the 'l'. Same with half, calf etc. (I'm not to sure about this explanation)

Spanish has far fewer vowel sounds, so the a,e,i,o and u are sufficient to define them all without help from unpronounced letters.

Does that help for a start? :)

Perikles has excellent examples, and I agree with his general statement that many spelling conventions often signal (or used to signal) a particular vowel quality.

The l+[consonant] convention does work to some degree, but it isn't as reliable in North American English as it is in British Received Pronunciation.

Usually "a(u)lk" is the closest to 'o' (walk, talk, balk, caulk).

Usually "alm" has the same vowel sound as the first syllable of "father" (alm, balm, calm, palm, psalm).

In a couple of regions, and especially in eastern Massachusets, some people with strong local accents pronounce "calf", "half", "can't", "bath" and a few other words with a sound that is closer to the first syllable of "father", but in most of North America these words have the same sound as the word "hat".

It's not just length: it's also the position in the mouth. See http://en.wikipedia.org/wiki/IPA_vowel_chart_with_audio . The horizontal axis is how far forward or back in the mouth the narrowest obstruction formed by the tongue is, and the vertical axis is how open the mouth is.

Counting the number of vowel sounds in English is difficult. Wikipedia lists 27 lexical sets which show vowel variation, including diphthongs. However, every dialect merges some of them (although not the same ones). See http://en.wikipedia.org/wiki/Interna...glish_dialects