Notes
This is the form recommended in the national standard reference work, A Gazetteer of Welsh Place-Names (University of Wales Press, 1967). One should not deviate from its recommendations without good reason.
This is the form that conforms to the principles of standard Welsh orthography.
According to the rules of Welsh orthography s should be followed by the consonant b not by the consonant p. It is not easy, however, to hear the difference between the combination sp and the combination sb in speech (compare ysbyty/yspyty).