Why is the letter A the shape it is?
Well, it started off as a picture of an ox's head (nowadays you have to be upside down to appreciate this). The link is that in those days the word for ox, Aleph, started with an A sound.
It was a good idea at the time, but unfortunately nowadays we call an ox an ox, so it's longer any help.
But how about if you could invent an alphabet where you could tell the sound of each letter from its shape?
In England, the most familiar alphabet with this feature (they're called featural alphabets) is Pitman Shorthand; but other, older alphabets used this system long before that.
There's the clever Korean script Hangul:
Hangul was in fact the script for which the term featural was invented. Look, for instance, at the connection between a and ya, and o and yo in the illustration.
Quite a few languages have featural elements to help readers along. Turkish and Japanese, for instance, sometimes use extra marks to describe the sort of noise a letter is supposed to make.
A featural alphabet might make similar sounds like t and d, which use the same sort of tongue movement (try it) similar in shape. In fact our own dear alphabet almost does this with the similar-looking letters b and p, which use similar movements of the lips.
Well, probably. But never mind.
Word To Use Today: feature. This word comes from the Anglo-French feture, from the Latin facere, to make. The term featural alphabet was made up by Geoffrey Sampson.