अ अ इति

The first अ is here विवृत or open; the second is संवृत or contracted. The open अ is now changed to contracted अ ॥ \In actual use the organ in the enunciation of the short अ is contracted; but it is considered to be open only, as in the case of the other vowels, when the vowel अ is in the state of taking part in some operation of Grammar. The reason for this is, that if the short अ were held to differ from the long आ in this respect, the homogeneousness mentioned in 1.1.9, would not be found to exist between them, and the operation of the rules depending upon that homogeneousness would be debarred. In order to restore the short अ to its natural rights, thus infringed throughout the Ashyadhyayi, Panini with oracular brevity in his closing aphorism gives the injunction अ अ; which is interpreted to signify--Let short अ be held to have its organ of utterance contracted, now that we have reached the end of the work in which it was necessary to regard it as being otherwise\. (Dr. Ballantyne).

Thus वृक्षः, प्लक्षः ॥ In this Grammar, the अ is regarded open or vivrita, when operations are performed with it: but in actual pronunciation it is contracted. The long आ and the pluta आ ३ are not meant to be included here in the open short अ; therefore those two are not contracted by this rule. Only the short अ consisting of one matra, with its various modifications is to be taken here. In other words the six shorts अ are only taken here, namely अ꣡, अ॒॒, अ॑, अँ꣡, अँ, अँ॑ ॥ For these six short open अs, there are substituted six contracted corresponding अ's See (l. 1. 9).