There is an case in a will where a person had the surname of "de Wit" and whose children spelt their surname as "de Witt" with two "T"'s. There are also other cases where the wives of "de Wit" husbands spelt their surname with two "T"'s.It would therefore appear that the surname "de Witt" in most cases was previous spelt "de Wit" and therefore has the same meaning. A few of the later immigrants did spell their surname as "de Witt"

Courtesy of Chris de Wit : Christoffel de Wit en Jan de Wit se nageslagte in Suid Afrika.

Other ways of spelling de Wit is found in early Cape Colony baptism registers such as de With.