Consonantal alphabets all developed from the Proto-Sinaitic script, which was the first alphabetic writing system. A pure consonantal alphabet will contain no vowels, although there are many alphabets that are considered to be consonantal which do contain a few vowels .
An example of a consonantal alphabet is Arabic
Due to the global influence of Islam, the Arabic alphabet is one of the most widespread writing systems in the world. There are about 221 million Arabic speakers worldwide. This language is found in Africa and Western and Central Asia, but is also spoken in ethnic communities in East Asia, Europe and the Americas. map_arabic (A map showing Arabic-speaking nations colored in yellow. Source: unesco.org)
The Arabic alphabet is used to write a number of other languages including Persian, Pashtu and Urdu.
arabic-alphabet (An image of the Arabic alphabet. Source: joaoleitao.com)
persian_alphabet_letters (The Persian alphabet. Source: iranchamber.com)
pashtu_sample (A sample of Pashtu writing. Source: uwf.edu)
619px-Urdu_alphabets (The Urdu alphabet. Source: wikimedia.org)
Arabic evolved from the Nabataens, who were a culture that developed a kingdom in modern-day Jordan during the 2nd century BCE. The Nabatean Aramic script, appeared in inscriptions until the 4th century CE, which is the same time that the first inscriptions in the Arabic alphabet began appearing in Jordan.
There are 28 letters in the traditional Arabic alphabet.
Most of the letters change form depending on their placement within a word (beginning, middle, or end), or whether they stand apart as their own word.
There are two variants of the Arabic alphabet. The first is the Kufic script, which is a more angular way of writing, and is believed to have been produced on hard surfaces like wood and stone. It is the older of the two Arabic variants, and was common in the early history of Islam. The second variant of Arabic is the Naskhi script, which is a more cursive way of writing. The Naskhi script appeared by the 11th century and eventually replaced Kufic script. Modern Arabic script developed from the Naskhi script.
Quran in Kufic( An image of the Quran written in Kufic script. Source: library.princeton.edu)
The Arabic script doesn’t contain letters for vowels. In order to designate a vowel, one must use diacritics, which is a mark placed over, under, or through a letter to indicate how it should be pronounced.
In addition to showing vowels, diacritics are used in Arabic to indicate a pause between words, or a glottal stop (shown by the hazma). Another diacritic used in Arabic is the suku:n, which indicates the absence of a vowel. Finally, there is the Shadda which deomnstrates the doubling of a consonant.