David Dunton Thomas was born August 21, 1930 to Claude H. and Ruth Dunton Thomas in Taiyuan, Shansi, China. His parents were both missionaries with the China Inland Mission (CIM). In 1934 the Thomas family returned to the United States on furlough, during which time they lived in Wheaton, Illinois. The Thomases returned to the foreign field in 1935. In May of 1936, Thomas's father died, after which time Thomas, his mother, and his sister settled at the CIM school for missionary children, located in Chefoo, Shantung, where Mrs. Thomas taught during their stay.

After the United States' entry into war against Japan in December, 1941, the Thomas family, as American citizens, were among the enemy nationals imprisoned by the Japanese in the school compound in Chefoo. All three were repatriated in 1943 and returned again to Wheaton, where they settled near David's grandfather. Thomas attended Wheaton Community High School from February 1944 until his graduation in June of 1947. He was accepted to Wheaton College and spent four years there where he earned his B.A. in Greek in 1951.

Upon completion of his college career, Thomas sought a future in missionary service. He was convinced of his duty to God, and wanted only to be "where and what God would have me be." In pursuit of a missionary career, Thomas continued his education at Columbia Bible College, where he earned a B.D. and M.A. in missions.

In 1953, Thomas joined Wycliffe Bible Translators and began work as a linguist and Bible translator for tribal people. He spent the spring of 1953 at Wycliffe's Jungle Camp in Ixtapa, Chiapas, Mexico. While at camp, Thomas was taught how to "make the most of whatever sort of tribal situation" arose, which involved learning basic survival skills and first aid.

After completing Jungle Camp, Thomas was assigned to the Summer Institute of Linguistics (SIL), in Manila, Philippines. While in the Philippines, he worked on Bible translation and the preparation of text materials, in tribal languages, to be used in the field. On May 28, 1956, while still in Manila, Thomas married Dorothy Fowler, a graduate of Penn State as well as of Columbia Bible College, where the couple had first met. His wife was also accepted by Wycliffe, and shared Thomas's interest in linguistics and Bible translation. The Thomases remained in the Philippines until their transfer to Vietnam in 1957.

Thomas's assignment in Vietnam involved doing linguistic analysis of the Chrau tribal language in preparation for Bible translation into that tongue, an assignment to which Thomas would devote over two decades. Since Chrau was an only an oral language, Thomas and his wife were responsible for (1) developing a written form for Chrau, (2)preparing literacy and educational materials, and (3) translating the New Testament.

While on furlough in 1960, the Thomases taught at the Wycliffe Language Course in Chigwell, Essex, England, where he was assigned to the grammar staff and she to the phonetics staff. They also went to Paris, France, where they visited linquists working with Vietnamese languages. Also during this furlough Thomas began work on his Ph.D. in linguistics at the University of Pennsylvania.

The Thomases returned to Vietnam in December of 1961 and took up residence in Xuanloc, the provincial capital of Longhanh. With the assistance of a Chrau tribesman, they threw themselves back into their linguistics work, concentrating their efforts on producing a series of Chrau language primers.

In 1962, Thomas was assigned to serve as Acting Director of SIL Vietnam, while Director Dick Pittman went on furlough. The Thomases spent two years in Saigon where David taught at the University of Saigon as well as performing administrative duties. After they returned to Xuanloc for a short period in 1964, the Thomases went to Kontum where they took charge of linguistics workshop. The primary focus of the Kontum institution was the analysis of different aspects of Vietnamese languages. In 1964, Thomas attended a meeting of the Translators Institute in Bangkok, Thailand, sponsored by the American Bible Society, and held for translators working throughout Southeast Asia. In 1966, Thomas helped teach a short Chrau Bible School. The primers he and his wife developed were put to use in this school, as well as in the provincial school system.

The Thomases went on furlough during 1966/1967. During this time, David completed work on his Ph.D., as well as taught linguistics at SIL in Grand Forks, North Dakota (SILND). En route back to Vietnam the Thomases taught an SIL summer school course in linguistics in New Zealand. Upon their return to Saigon in 1968, the Thomases discovered that the Kontum workshop center had been demolished during the Tet celebration of 1968. They immediately rented a house in Nhatrang, where they re-established the workshop center. Back in Xuanloc they held a second Chrau school. During this time period, Viet Cong military activity began to become a noticeable feature of the Thomases' life in Vietnam.

In June of 1969 Thomas attended Wycliffe's administrative conference in Mexico, where he served as a delegate. After long delays, the scripture, hymns, and literacy books translated by David and Dorothy were printed and distributed to Chrau villagers in 1972. Some distribution problems arose due to increased Viet Cong presence in the area. During this same year, Wycliffe opened its new headquarters for Vietnam work in Saigon. Following furlough in 1973, Thomas was appointed Deputy Director for the Cambodian extension of the Vietnam branch. This assignment included administrative as well as teaching responsibilities. He left that country in 1975 because of the worsening political situation.

By 1978 the Thomases had moved to Thailand where David served as instructor of linguistics and Bible introduction at Mahidol University in Bangkok. During this year, although no longer working out of Vietnam, the Thomases completed their translation of the Chrau New Testament, which was to be published in 1979. They then started working on a Bible translation for Northern Khmer.

While on furlough during 1979, the Thomases spent time in Paris and London where they met with refugee workers. Thomas also taught linguistics at SILND. Upon their return to Thailand in 1980, Thomas continued work in administration as well as teaching at Mahidol University in Bangkok. He also produced a grammar text book. The Thomases continued their work in Bangkok until 1993, with David teaching and both he and Dorothy working on Khmer translation. They then moved to Waynesville, North Carolina, USA. He died April 14, 2006.