Iranian (northwestern) group of languages native to Iran, spoken by 110,000 mainly in the Semnan province (Semnan (city)), where they form a minority of about 20% of the total population.
Some researchers classify these languages as dialects of the Semnani language. Some listings have 6 Semnani languages, while Ethnologue only has 4. The two variants not listed as independent languages with Ethnologue are Biyabunaki and Aftari.
There are many shared linguistic features and structures with Caspian languages (Gilaki and Mazandarani).
Confusingly, one of the Samnani languages is called simply Semnani. It is spoken by 60,000 (2007), and a living language. Most Sangisari speakers also have good conduct of Persian.
Biyabunaki is by Ethnologue as a dialect of Semnani.
Sangsari, is spoken by 36,000 (2006 census), mainly in the town of Sangsar and surrounding villages. It is very much a living language. Most Sangisari speakers also have good conduct of Persian. It is close to Lasgerdi.
Sorkhei is spoken by 10,000 (2006 census) in the village of Sorkheh.
Aftari is by Ethnologue as a dialect of Sorkhei.
Lasgerdi is only spoken by 1,000 (2006 census), in the village of Lasjerd (another spelling for the language is Lasjerdi). It is close to Sorkhei. There is a smaller percentage of Lasgerdi speakers, compared to other Semnani languages, that speak Persian too. This reflects great isolation.