The Kaithi script developed from the Gupta script and was used from at least the 16th century to write a number of languages, including Bhojpuri, Maghadi, Urdu, Awadhi, Maithili and Bengali.
During the British colonial period the use of Kaithi was discouraged, except in Bihar, where it was made the official script of government offices and courts. As a result it is also known as the Bihar script. Elsewhere it was used mainly by the Kayastha, a Brahmin caste made up mainly of scribes and clerks, and the name Kaithi is derived from Kayastha, which means 'scribe' in Sanskrit.
Until the early 20th century Kaithi was widely used, but since then it has been largely replaced by Devanagari or other scripts, although it is apparently used to some extent in personal correspondence in rural areas.
Bhojpuri, Maghadi, Urdu, Awadhi, Maithili and Bengali.
Source: http://www.scribd.com/doc/52997045/Stotra-in-Kaithi-Script-Rajendra
Information about Kaithi
http://scriptsource.org/cms/scripts/page.php?item_id=script_detail&uid=fhadc85hgh
http://en.wikipedia.org/wiki/Kaithi
http://unicode.org/charts/PDF/U11080.pdf
Kaithi font
http://www.fontineed.com/font/KaithiOTS
Ahom, Badaga, Balinese, Batak, Baybayin (Tagalog), Bengali, Brahmi, Buhid, Burmese, Chakma, Cham, Dehong Dai, Devanagari, Dhives Akuru, Ethiopic, Evēla Akuru, Gondi, Grantha, Gujarati, Gupta, Gurmukhi, Hanuno'o, Javanese, Jenticha, Kaithi, Kannada, Kharosthi, Khmer, Khojki, Kulitan, Lanna, Lao, Lepcha, Limbu, Lontara/Makasar, Malayalam, Manpuri, Modi, Mongolian Horizontal Square Script, New Tai Lue, Oriya, Pahawh Hmong, Pallava, Phags-pa, Ranjana, Redjang, Shan, Sharda, Siddham, Sindhi, Sinhala, Sorang Sompeng, Sourashtra, Soyombo, Sundanese, Syloti Nagri, Tagbanwa, Takri, Tamil, Telugu, Thai, Tibetan, Tikamuli, Tocharian, Tolong Siki, Tulu, Varang Kshiti