| Frank Siebert | |
| Birth Name: | Frank Thomas Siebert, Jr. |
| Birth Date: | 2 April 1912 |
| Birth Place: | Louisville, Kentucky, U.S. |
| Death Place: | Bangor, Maine, U.S. |
| Burial Place: | West Laurel Hill Cemetery, Bala Cynwyd, Pennsylvania |
| Occupation: | Pathologist |
| Children: | 2 |
Frank Thomas Siebert Jr. (April 2, 1912January 23, 1998) was an American pathologist who became a leading authority on Algonquian languages, including Penobscot, for which he compiled a dictionary.
Siebert was born in Louisville, Kentucky, on April 2, 1912, and spent the first five years of his life in Nashville, Tennessee. In 1917, his family moved first to Philadelphia and then to Merion Station, Pennsylvania, where he grew up.
He attended Haverford College, studying chemistry and graduating in 1934.
Siebert started as a medical pathologist before leaving medicine to focus on linguistics. He studied medicine at the medical school of the University of Pennsylvania graduating in 1938. Apart from his medical studies at Penn, he was influenced by anthropologist Frank Speck in his interest in Native American languages. Traveling to other universities, he was also influenced by Franz Boas and Edward Sapir. In 1969, he became a Guggenheim fellow.
In 1980, he received a grant from the National Endowment for the Humanities for the creation of a Penobscot dictionary, a project that he had been working on since at least 1968.
Ives Goddard of the Smithsonian Institution called Siebert "clearly the most brilliant and most competent avocational linguist working on Native American languages that there has ever been, hands down." Karl Teeter, commenting on Siebert, called him "the dean of Algonquian linguistics".
In 1956, he married Marion Paterson, with whom he had two daughters. The marriage broke down in 1961, and divorce followed in 1964.
He was described as an eccentric and recluse. He collected rare books.
Siebert died in Bangor, Maine, on January 23, 1998, at the age of 85, after suffering for several years from cancer of the urinary tract and ensuing complications. He was buried with his mother and father at West Laurel Hill Cemetery in Bala Cynwyd, Pennsylvania.
Following his death, his collection of books and antiquarian items was sold at Sotheby's for $12.5 million, which was split between his two daughters. His dictionary and field-work materials were bequeathed to the American Philosophical Society.