A third method of reduplication is by the lengthening of an initial vowel. This follows a pattern similar to the temporal augment. A fourth method of reduplication is by repeating both the initial vowel and consonant and by lengthening the initial vowel. There is no sure way to determine which method of reduplication will be used in any given verb. The safest procedure is to check the principal parts.
Reduplication occurs in all moods and in all verbals .
This differs from the augment which occurs in the indicative mood only of the imperfect and aorist tenses. The perfect, active tense is based on the fourth principal part. The connecting vowel is a . The forms for the middle voice and the passive voice are identical. When the stem ends in a consonant, however, certain contractions and euphonic changes occur.