There is vocalisation of the semi-vowel y of the affix ṣyaṅ [[4.1.78]] when followed in a tat-puruṣa compound, by the words putra and pati,
When the words पुत्र and पति are the second members; forming a Tatpurusha compound, there is samprasarana (vocalising the semi-vowels) of the affix ष्यङ् of the preceding. That is य् is changed into इ ॥ Thus करीषस्येव गन्धोऽस्य = करीषगन्धिः (a Bahuvrihi compound taking the samasanta affix or rather substitute इ by 5.4.137 करीषगन्धैरपत्यम् = करीषगन्धि + अण् 4.1.92 = करीषगन्धः ॥ The feminine of this will be formed by adding ष्यङ् 4.1.78. Thus we have कारीषगन्ध्या (see 4.1.78). Now in forming the Tatpurusha compound of this word with पुत्र or पति, the final य् will be changed into इ and we have कारीषगन्धीपुत्रः, कारीषगन्धीपतिः ॥ The आ of या becomes merged into इ 6.1.108, and the short इ is lengthened 6.3.139. So also कौमुदगन्धीपुत्रः or कौमुदगन्धीपतिः ॥
Why do we say \of the affix ष्यङ्\? Observe इभ्यापुत्रः, क्षत्रियापुत्रः ॥
Why do we say \when followed by पुत्र or पति\? Observe कारीषगन्ध्याकुलम्, कौमुदगन्ध्याकुलम् ॥
Why do we say \when forming a Tatpurusha compound\? Observe कारीषगन्ध्यापतिरस्य ग्रामस्य = कारीषगन्ध्यापतिरयं ग्रामः ॥ It is a Bahuvrihi compound.
The affix ष्यङ् is here the feminine affix य followed by चाप् (आ) (see 4.1.77 and 4.1.74.
A general maxim relating to all affixes is \an affix denotes whenever it is employed in Grammar, a word-form which begins with that to which that affix has been added, and ends with the affix itself: प्रत्ययग्रहणे यस्मात् स विहितस्तदादेस्तदन्तस्य ग्रहणम्\॥ This maxim, however, does not apply in case of feminine affixes, where we have this rule \a feminine affix denotes whenever it is employed in a rule, a word-form which ends with that affix, but which need not necessarily begin with that to which the affix has been added, but where the word form is subordinate: \स्त्रीप्रत्यये चानुपसर्जने न\॥ Thus we have परमकारीषगन्ध्यायाः पुत्रः = परमकारीषगन्धीपुत्रः and so also परमकारीषगन्धीपतिः ॥ Not so when the word is an upasarjana or subordinate in a compound. As अतिक्रान्ता कारीषगन्ध्याम् = अतिकारीषगन्ध्या, तस्य पुत्रः = अतिकारीषगन्ध्यापुत्रः, अतिकारीषगन्ध्यापतिः ॥
This vocalisation takes place when पुत्र and पति alone, not compounded with any other word, stand at the end : not so when a word beginning or ending with these words follows. Thus कारीषगन्ध्यापुत्रकुलं, कारीषगन्ध्यापरमपुत्रः &c.
Though a word ending in ष्यङ् may have many semi-vowels, yet the vocalisation takes place of the affix य (ष्यङ्) only, according to the maxim निर्दिश्यमानस्यादेशा भवन्ति \substitutes take the place of that which is actually enunciated\.
The word संप्रसारण has regulating influence upto 6.1.44 inclusive. The rules of vocalisation (change of semi-vowels into vowels) is contained in these sutras.
Vart:- Prohibition must be stated when पति and पुत्र follow the word गौकाक्ष्य ॥ As गौकाक्ष्यापुत्रः, गौकाक्ष्यायातः instead of गौकाक्षीपुत्रः &c.,