The Younger Futhark, also called Scandinavian runes, is a runic alphabet, a reduced form of the Elder Futhark, consisting of only 16 characters, in use from about the 9th century, after a "transitional period" which lasted during the 7th and 8th centuries. The reduction, somewhat paradoxically, happened at the same time as phonetic changes led to a greater number of different phonemes in the spoken language, when Proto-Norse evolved into Old Norse. Thus, the language included distinct sounds and minimal pairs which were not separate in writing.