Cyrillic script consonants from the older Glagolitic alphabet for sounds not found in Greek. Tradition holds that Cyrillic and Glagolitic were formalized either by Saints Cyril and Methodius who brought Christianity to the southern Slavs, or by their disciples. Paul Cubberley posits that although Cyril may have codified and expanded Glagolitic, it was his students in the First Bulgarian Empire under Tsar Simeon the Great that developed Cyrillic from the Greek letters in the 890s as a more suitable script for church books. Later Cyrillic spread among other Slavic peoples, as well as among non-Slavic Vlachs. Cyrillic and Glagolitic were used for
Latin-script alphabet respective alphabet sequences. In some languages, digraphs are included in the collation sequence (e.g. Hungarian CS, Welsh RH). The International Phonetic Alphabet is also derived mainly from the Latin script. Coverage of the letters of the ISO basic Latin alphabet can be and additional letters can be Most alphabets have the letters of the ISO basic Latin alphabet in the same order as that alphabet. Some alphabets regard digraphs as distinct letters, e.g. the old Spanish alphabet had CH and LL sorted apart from C and L. Some Spanish dictionaries still list "ll" separately. Some alphabets sort letters that have