It is generally agreed that the written form of a natural language is the written record of the oral form. Naturally the written form should agree with the oral form. In other words, the sound should be similar to the form. This is fairly true of English in its earliest stage i.e. Old English. The speech of the time was represented very much more faithfully in writing than it is today. With the development of the language, more and more differences occur between the two. The internal reason for this is that the English alphabet was adopted from the Romans, which does not have a separate letter to represent each sound in the language so that some letters must do double duty or work together in combination.