The Somali Latin alphabet has been the official writing script in Somalia since 1972. It was developed by the Somali linguist Shire Jama Ahmed specifically for transcribing the Somali language, and is based on the Latin script. The Somali Latin alphabet uses all letters of the English Latin alphabet except p, v and z. There are no diacritics or other special characters, although it includes three consonants digraphs: DH, KH and SH. Tone is not marked and a word-initial glottal stop is also not shown. Capital letters are used for names and at the beginning of a sentence.