Tha: The Fourth Letter of the Arabic Script

Tha is the fourth letter of the modern Arabic order and the shared bowl skeleton carrying three dots above, the only Arabic letter pointed with three. It joins on both sides and reduces to a tooth with its three dots at the beginning and in the middle of a word. Its sound is the voiceless dental fricative heard at the start of the English word thin, a sound Arabic preserved where several of its sister languages lost it, and one that many spoken Arabic dialects have since merged with t or with s.

Tha is a sun letter, so the lam of the definite article assimilates to it in speech although it is still written.

The letter is one of six that Arabic added to the twenty-two letter sequence it inherited from the Northwest Semitic scripts, and its position records that history plainly. In the modern order, which arranges the letters by shape, tha sits next to the ba and ta it resembles. In the older abjad order it is not in the body of the list at all but among the six letters appended at its end, where it carries the numeral value five hundred. Because the inherited names came with the inherited letters, tha has no Northwest Semitic name behind it, no cognate letter in Hebrew or Syriac to which its name can be traced, and no reconstructed pictographic sense of the kind offered for aleph or beth.