a. To the present stem: as, amá-t-um, délé-t-um, audí-t-um.
b. To the root, with or without i: as, cap-t-um (capió, CAP), moni-t-um (moneó, MON used as root), cás-um (for cad-t-um, CAD), léc-t-um (LEG).
NOTE 1: By phonetic change dt and tt become s (défénsum, versum for dé-fend-t-um, vert-t-um); bt becomes pt (scríp-t-um for scríb-t-um); gt becomes ct (r=ec-t-um for reg-t-um).[For these modifications of the supine stem, see § 15. 5, 6, 10.]
NOTE 2: The modifications of the present stem sometimes appear in the supine: as, tínc-t-um (tingó, TIG), tén-s-um for tend-t-um (ten-d-ó, TEN).
NOTE 3: The supine is sometimes from a lost or imaginary verb-stem: as, petí-t-um (as if from peti-ó, petí-re, PET).
NOTE 4: A few verbs form the supine stem in s after the analogy of verbs in d and t: as, fal-s-um (fall=o), pul-s-um (pelló).