The Santali Latin alphabet was invented in the 1890s by the Norwegian missionary Paul Olaf Bodding, and is still used by most Santhals, especially the members of the Northern Evangelical Lutheran Church (NELC).
Since the Santhals have no alphabet of their own, they adopted the Roman script, using certain diacritical marks to denote sounds that differ from those these letters have in English. This was done under the influence of Christian missionaries who were the first to take an active interest in the study of the Santal language.
The language is also written using the Ol Chiki script.
References
Santali Latin alphabet Wikipedia(Text) CC BY-SA