It is doubtful if the Victorian Londoner needed any warning, for the artful mobsmen, toolers, whizzers and dippers, together with their stickman accomplices, were everywhere in the crowds, in the underground, on railway trains […]

The sege houses in þe West~orcherd were graunte to hym.

Coordinate term: substitution

Thus, underlying ‘agtus’ was converted first into ‘āgtus’ by the vowel lengthening rule, and then into ‘āktus’ by the ancient persistent rule. This example has previously been interpreted as indicating that new rules can enter a phonology elsewhere than at depth I.