Sandhi (a): Svarasandhi

The rules dealing with the combination of two vowels are regarded as Svarasandhi or acsandhi. The rule that prescribes a very important substitution is iko yaṇaci (6/1/77).

The rule iko yaṇaci is illustrated in the verse.

nyasyāśu pāṇāvasimujjvalaṃ rathe gavyādvijastrījanarakṣṇadakṣiṇam |
akrayyamakṣayyamupeyuṣā yaśo rakṣye hi bhāvyaṃ prabhuṇādayālunā || (1/48 Vāsudevavijaya)

In this verse, the word nyasya which is a verb in loṭlakāra, means sthapaya | It forms the example for this rule. ni+ asya→ nyasya | The rule means, in the matter of combining letters, the semi vowels ya, v, r, l (yaṇ) are substituted in place of i, u, ṛ, lṛ (ik short and long), when a vowel immediately follows it.

In the example ni asya, the letter i of ni is followed by a vowel a, and it is substituted by y | Then the form will be n y asya → nyasya |

The next rule eco'yavāyāvaḥ (6/1/78) has several examples in Vāsudevavijaya. There are about five examples are given by Vāsudeva. The above verse, itself holds the example for this rule.

The rule ordains that for e, ai, o, au (ec) are respectively substituted by ay, av, āy and āv when followed by a vowel.

The words, pāṇāvasim can be split accordingly this rule, as pāṇau + asim | Here the letter au followed by a which is a vowel, is substituted by āv and the form will be pāṇāvasim ||

The rule vānto yi pratyaye (6/1/79) ordains that when an affix beginning with ya follows, o and au are substituted by av and āv respectively. In the same verse quoted above from Vāsudevavijaya, gives example for this rule as gavya which is formed as go+ ya | An affix ya comes from the word go as per the rule khalagorathāt | Then the word go is followed by ya and the o will be substituted by av and the form is g av ya→ gavya |

The same phonetic combination continues in the following rule viz. dhātostannimittasyaiva (6/1/80), but with a different condition altogether. It informs that the o and au endings of the root when immediately followed by the affix beginning with ya are substituted by av | The example given for this rule in the above quoted verse from Vāsudevavijaya is bhāvyam | The word is resulted from the root bhū | From this root, an affix ṇyat is employed by the rule orāvaśyake |

bhū+ ṇyat→ bho + ya→ bhāv+ ya→ bhāv + ya (ādivṛddhi)→ bhāvyam ||

When taking into consideration the next rule kṣayyajayyau śakyārthai (6/1/81), it states that, when the root kṣi to decline, and ji to conquer are followed by Kṛtya affix ya, e is substituted by ay resulted in kṣayya and jayya convey the sense 'capable of' or 'to be possible to do'. These two are irregular forms. In the verse, the word kṣayya is employed and which is declined irregularly by this rule.

In the same vein, the very next rule krayyastadarthe (6/1/82), Pāṇini enjoins that in krayya, e is substituted by ay, if it means 'something for better'. The word akrayya in the verse, is declined irregularly by the rule krayyastadarthe |

Then, Pāṇini introduces a new type of substitution. The rule ekaḥ pūrvarayoḥ (6/1/84) is a domain. According to this rule the phrase pūrvaparayoḥ is always to be supplied, in the construction of the rules, to which shows its extended meaning (6/1/11). There is a single substitution for the preceding and following one.

Under this sutra, the first rule enjoining this single substitution i.e. ekādeśa is Guṇasandhi by the rule ād guṇaḥ (6/1/87). According to this rule, when the final ā of the preceding word when immediately followed by a simple vowel, there will be a single substitution for both. In the same verse, Vāsudeva illustrated this rule also. Example for this rule is gives as rathaḥ |

Likewise, Vāsudeva gives many illustrations for the rule of Svarasandhi. Almost all rules regarding this section is illustrated in Vāsudevavijaya except five or six rules.