53. Most of the consonants are pronounced as in English. The following
points must be noticed:
54. #b# before #a# surd, as #s# or #t#, has the sound of #p#. The
spelling #b# is here simply etymological: as, #abs#, pronounced _aps_
(the #b# retained in spelling because of #ab#); #urbs#, pronounced
_urps_ (the #b# retained because of the oblique cases #urbis#, #urbī#,
etc.); #obterō#, pronounced _opterō_ (Quint. 1, 7, 7), where the
spelling of the preposition #ob# was kept (164).