Most scripts used to write Semitic languages are abjads – a type of alphabetic script that omits some or all of the vowels, which is feasible for these languages because the consonants in the Semitic languages are the primary carriers of meaning. Among them are the Ugaritic, Phoenician, Aramaic, Hebrew, Syriac, Arabic, and South Arabian alphabets. The Ge'ez script, used for writing the Semitic languages of Ethiopia and Eritrea, is technically an abugida – a modified abjad in which vowels are notated using diacritic marks added to the consonants at all times, in contrast with other Semitic languages which indicate diacritics based on need or for introductory purposes. Maltese is the only Semitic language written in the Latin script and the only Semitic language to be an official language of the European Union.
The Semitic languages are notable for their nonconcatenative morphology. That is, word roots are not themselves syllables or words, but instead are isolated sets of consonants (usually three, making a so-called triliteral root). Words are composed out of roots not so much by adding prefixes or suffixes, but rather by filling in the vowels between the root consonants (although prefixes and suffixes are often added as well). For example, in Arabic, the root meaning "write" has the form k-t-b. From this root, words are formed by filling in the vowels and sometimes adding additional consonants, e.g. كتاب kitāb "book", كتب kutub "books", كاتب kātib "writer", كتّاب kuttāb "writers", كتب kataba "he wrote", يكتب yaktubu "he writes", etc.
1538 comparison of Hebrew and Arabic, by Guillaume Postel – possibly the first such representation in Western European literature
The similarity of the Hebrew, Arabic and Aramaic languages was accepted by Jewish and Islamic scholars since medieval times. The languages were familiar to Western European scholars due to historical contact with neighbouring Near Eastern countries and through Biblical studies, and a comparative analysis of Hebrew, Arabic, and Aramaic was published in Latin in 1538 by Guillaume Postel. Almost two centuries later, Hiob Ludolf described the similarities between these three languages and the Ethiopian Semitic languages. However, neither scholar named this grouping as "Semitic".
In the Mosaic Table of Nations, those names which are listed as Semites are purely names of tribes who speak the so-called Oriental languages and live in Southwest Asia. As far as we can trace the history of these very languages back in time, they have always been written with syllabograms or with alphabetic script (never with hieroglyphs or pictograms); and the legends about the invention of the syllabograms and alphabetic script go back to the Semites. In contrast, all so called Hamitic peoples originally used hieroglyphs, until they here and there, either through contact with the Semites, or through their settlement among them, became familiar with their syllabograms or alphabetic script, and partly adopted them. Viewed from this aspect too, with respect to the alphabet used, the name "Semitic languages" is completely appropriate.
Previously these languages had been commonly known as the "Oriental languages" in European literature. In the 19th century, "Semitic" became the conventional name; however, an alternative name, "Syro-Arabian languages", was later introduced by James Cowles Prichard and used by some writers.