Thelma "Tybie" Thall Sommer won two World Table Tennis Championships. In 1948, she and Richard Miles were the first Americans to win the World's Mixed Doubles title. One year later in Stockholm, she and her United States team captured the women's World Championship (Corbillion Cup).

Thall Sommer and Miles won the English Open Mixed Doubles in 1949, and she captured the English Open Women's Doubles (with Peggy McLean).

Tybie is the younger sister of Leah Thall Neuberger (IJSHOF 1999). The sisters won three consecutive U.S. National Women's Doubles championships–1947-48-49, and Canadian National Doubles in 1947 and 1948.

The Ohio-born champion was inducted into the U.S. Table Tennis Association Hall of Fame in 1980. In 2005, Tybie and sister Leah were recipients of the USA Table Tennis Mark Mathews Lifetime Achievement Award.

In 2012. Tybie presented the inaugural "Thall Sisters Cup", USTTA's award to the U.S. Open Women's Singles Table Tennis Champion.