Tehriyali is spoken in the Present day Tehri district of the state of Uttrakhand.
It was once the official language of the Tehri state and was widely used for formal and informal purposes. It was the language of the royals. After integration of the Tehri state into India, Tehriyali was taken down as the official language of the state and it's place was given to Hindi.
Presently the official languages of the state of Tehri are Hindi & Sanskrit.
Currently Tehriyali is in the endangered catagory and is said to go extinct within a few decades. It has not been given a separate Identity till date by the government and is considered as a Hindi dialect.
British linguist GA Grierson is said to have last surveyed and studied the Tehriyali language.
This was 122 years back, in 1909.