forms with an initial prevocalic laryngeal could not be affected by the loss, since contractions of reduplication from roots of the HEC-type occurred much earlier, at the common Indo-European level.

But there are irregular verbs! The big two you need to know are ‘to go’ - ‘ir’ and ‘to be’ - ‘ser’. Luckily, they’re both the same in the preterite. They become: ‘fui ...