The word alphabet can be defined as a set of letters or symbols that was created for written language. There are two main characteristics of an alphabet. The first characteristic is letters. "Letter is a mark or character used as the representative of a sound; or of an articulation of human organs of speech; a first element of written language" (BD, 2003). Generally, letters in written language are comprised of consonants and vowels. For example, the English alphabet consists of 26 letters. It is made up of 21 consonants and 5 vowels, whereas the Arabic alphabet is comprised of 25 consonants and 10 vowels (TOG, 1997). Consonants are any speech sounds, which are made by stopping the air through the mouth. Unlike consonants, vowels are speech sounds made without closing the air passage in the mouth or throat (LD, 1995). In English, the vowels are `A', `E', `I', `O', and `U'. When these vowels are combined with consonants, they create words. Almost every word consists of at least one vowel. For example, the word `dog' is comprised of two consonants and one vowel. The consonants are`d' and `g', while the vowel is `o'. The second characteristic is symbols. "Symbol is a figure, or sign conventionally standing for some object, process or other thing" (TWBD, 1991). For instance, a Greek symbol, ð, has a value of approximately 3.1416. Another example is that Ó refers to sum up the numbers. As mentioned above, the nature of alphabet can be easily described as a series of letters or symbols used for writing.