The Younger Futhark, also called Scandinavian runes, is a runic alphabet and a reduced form of the Elder Futhark, with only 16 characters, in use from about the 9th century, after a "transitional period" during the 7th and 8th centuries. The reduction, somewhat paradoxically, happened at the same time as phonetic changes that led to a greater number of different phonemes in the spoken language, when Proto-Norse evolved into Old Norse. Also, the writing custom avoided carving the same rune consecutively for the same sound, so the spoken distinction between long and short vowels was lost in writing. Thus, the language included distinct sounds and minimal pairs that were written the same. The Younger Futhark is divided into long-branch (Danish) and short-twig (Swedish and Norwegian) runes; in the 10th century, it was further expanded by the "Hälsinge Runes" or staveless runes. The lifetime of the Younger Futhark corresponds roughly to the Viking Age. Their use declined after the Christianization of Scandinavia; most writing in Scandinavia from the 12th century was in the Latin alphabet, but the runic scripts survived in marginal use in the form of the medieval runes (in use ca. 1100–1500) and the Latinised Dalecarlian runes (ca. 1500–1910). History Usage of the Younger Futhark is found in Scandinavia and Viking Age settlements abroad, probably in use from the 9th century onward. During the Migration Period Elder Futhark had been an actual "secret" known to only a literate elite, with only some 350 surviving inscriptions. Literacy in the Younger Futhark became widespread in Scandinavia, as witnessed by the great number of Runestones (some 3,000), sometimes inscribed with almost casual notes. During a phase from about 650 to 800, some inscriptions mixed the use of Elder and Younger Futhark runes. Examples of inscriptions considered to be from this period include DR 248 from Snoldelev, DR 357 from Stentoften, DR 358 from Gummarp, DR 359 from Istaby, and DR 360 from Björketorp, and objects such as the Setre Comb (N KJ40). Ög 136 in Rök, which uses Elder Futhark runes to encrypt part of the text, and Ög 43 in Ingelstad, which uses a single Elder Futhark rune as an ideogram, are also sometimes included as transitional inscriptions. By the late 8th century, the reduction from 24 to 16 runes was complete. The main change was that the difference between voiced and unvoiced consonants was no longer expressed in writing. Other