Ad. adjacent like vowels contract and lengthen; [uu|ii|aa] > [ū|ī|ā]

Ad. adjacent like vowels contract and lengthen; [uu|ii|aa] > [ū|ī|ā]
As consonant disappeared (such as [ʔ], [ɣ]) or became vocalic ([w], [j]), once separate vowels could come into contact. In the case where those vowels were the same, they would contract into a single vowel, lengthening in the process (SD/424). This rule seems to have remained functional throughout the development from primitive to Classical Adûnaic. In cases where one of the vowels was already long, this would produce over-long-vowels in older forms of the language (SD/423), though apparently these were reduced to ordinary long vowels by the time of Classical Adûnaic.

Reference ✧ SD/424

Phonetic Rule Elements

[uu] > [ū] ✧ SD/424 ([uu] > [ū])
[ii] > [ī] ✧ SD/424 ([ii] > [ī])
[aa] > [ā] ✧ SD/424 ([aa] > [ā])

Phonetic Rule Examples

paa > pā aa > ā ✶Ad. pa3a > Ad. ✧ SD/426