Abjads

Chapter 1 said most alphabets descend from one source, Proto-Sinaitic. This chapter follows the first branch: the Phoenician script and the two great scripts that grew from it, Hebrew and Arabic. All three write consonants and leave the reader to supply the vowels.

The Word "Abjad"

• The term was introduced in 1990 by Peter T. Daniels, per the Abjad article.
• The name comes from the first four letters of the Arabic alphabet in their traditional order, which correspond to ʾa, b, j, d.

Why Consonants Are Enough

The article says Semitic words are built from a root of usually three consonants, with vowels marking inflected or derived forms. Its example is the Arabic root K-T-B, which yields kataba "he wrote", yaktubu "he writes" and maktabah "library". The three consonants carry the core meaning, so a reader who knows the language can usually infer the word. The article suggests this helps readers recognise common roots, but marks that claim as lacking citations.

Phoenician

From Wikipedia's Phoenician alphabet article (first 100,000 of 190,094 characters read).

• Size and direction. 22 consonant letters, written right to left. Late varieties sometimes used matres lectionis to mark some vowels.
• Dates. c. 1050 to 146 BC. The article notes 1050 BC is a conventional start date, since no Phoenician inscriptions are securely dated to the 11th century; the oldest known are from the 10th century.
• Origin. It developed directly from the Proto-Sinaitic script of the Late Bronze Age, which was derived from Egyptian hieroglyphs.
• Spread. Phoenician maritime merchants carried it across the Mediterranean, and adaptations appeared from the 9th century BC. The article credits its simple design, "one sound was represented by one symbol", as a key reason for its success.
• Letter names. Each letter has a name and a meaning: aleph means "ox" and bet means "house". Some meanings are uncertain, such as gimel ("throwing stick" or "camel").

The family tree

Hebrew and Arabic

• "Impure" abjads. The Abjad article calls Arabic, Hebrew, Aramaic and Pahlavi impure because some consonant letters double as vowel letters (matres lectionis). This began rarely and became more common over time.
• When vowels are written. Vowel marks are optional and "not the dominant (or literate) form". The Arabic article says everyday writing, publications and street signs usually omit them, while the Qur'ān, children's books and grammar texts usually include them.
• Other languages. The Arabic script is also used for Persian and Urdu, with extra letters such as پ added in adaptations.

Seeing It in Python

My own example; I ran it and copied the output. It writes the root K-T-B bare and then with a short vowel mark after each consonant.

The bare root is 3 code points; with a short-vowel mark after each consonant it is 6. In Hebrew, "shalom" is 4 code points bare and 7 with niqqud. The vowel marks are separate code points, which fits their being optional additions. The bidirectional property R marks the Hebrew letters as right-to-left, against L for the Latin letter. Phoenician has its own Unicode block (the article gives U+10900 to U+1091F), and its first letter is named ALF.

Try It Yourself