1. In step 1, how did we narrow down to ‘जस्’ from the list of 21 affixes? What are the rules involved here?
Answer: As per the सूत्रम् 1-4-103 सुपः – The सुप् affixes listed in 4-1-2 (सु-औ-जस्)-(अम्-औट्-शस्)-(टा-भ्याम्-भिस्)-(ङे-भ्याम्-भ्यस्)-(ङसि-भ्याम्-भ्यस्)-(ङस्-ओस्-आम्)-(ङि-ओस्-सुप्) are in sets of three and in each set there is a singular, dual and plural affix. Note: There are seven sets, the first set (सु-औ-जस्) is for प्रथमा-विभक्तिः, second set (अम्-औट्-शस्) is for द्वितीया-विभक्तिः and so on, until the seventh set (ङि-ओस्-सुप्) which is for सप्तमी-विभक्तिः।

The first set (प्रथमा-विभक्ति: – nominative case) consists of three affixes is ‘सुँ’ (singular), ‘औ’ (dual) and ‘जस्’ (plural.) In the present example, since the intention of the speaker is to use the nominative case in the plural form the affix ‘जस्’ is applied to ‘सर्व’।

2. How is the form ‘सर्वे’ different from the प्रथमा-विभक्ति-बहुवचनम् of राम-शब्दः? What is the reason for the difference?
Answer: The प्रथमा-विभक्ति-बहुवचनम् of राम-शब्दः is derived as follows –
राम + जस् । By 4-1-2 स्वौजसमौट्छष्टाभ्याम्भिस्ङेभ्याम्भ्यस्ङसिभ्याम्भ्यस्ङसोसाम्ङ्योस्सुप्‌ ।
= राम + अस् । By 1-3-7 चुटू, 1-3-9 तस्य लोपः। Note: 1-3-4 न विभक्तौ तुस्माः prevents the ending letter ‘स्’ of ‘जस्’ from getting the इत्-सञ्ज्ञा।
= रामास् । By 6-1-102 प्रथमयो: पूर्वसवर्णः ।
= रामाः । रुँत्व-विसर्गौ by 8-2-66 ससजुषो रुः and 8-3-15 खरवसानयोर्विसर्जनीयः।

In the derivation of the प्रथमा-विभक्ति-बहुवचनम् of सर्व-शब्दः, the सूत्रम् 7-1-17 जस: शी applies in step 2, since ‘सर्व’ gets the सर्वनाम-संज्ञा as per the सूत्रम् 1-1-27 सर्वादीनि सर्वनामानि – The list of terms starting with ‘सर्व’ are called सर्वनामानि (pronouns.) Hence we get the form सर्वे as shown in the post.

3. Commenting on the सूत्रम् 7-1-17 जसः शी (used in step 2) the सिद्धान्तकौमुदी says  – अनेकाल्त्वात्सर्वादेशः। On this the तत्त्वबोधिनी says – न तु शित्त्वादिति भावः। Please explain.
Answer: As per the सूत्रम् 7-1-17 जस: शी – Following a pronoun ending in short ‘अ’ the nominative plural ending ‘जस्’ is replaced by ‘शी’। Now as per 1-1-52 अलोऽन्त्यस्य only the ending letter ‘स्’ of ‘जस्’ should be replaced by ‘शी’। But by the rule 1-1-55 अनेकाल्शित् सर्वस् – A substitute (आदेश:) which is अनेकाल् (has more than one letter) or has ‘श्’ as a marker, takes the place of the entire term which is in the sixth case (in the सूत्रम् which prescribes the substitution.) Now the question is, does 1-1-55 apply here because ‘शी’ is अनेकाल् (has more than one letter) or because it has ‘श्’ as a marker?
As explained in the next question, ‘शी’ does not have the designation of प्रत्ययः until it actually replaces ‘जस्’। Hence, prior to the replacement, the सूत्रम् 1-3-8 लशक्वतद्धिते (which requires the term to have the designation प्रत्ययः) cannot apply. Therefore, 1-1-55 applies on the basis that ’शी’ is अनेकाल् (has more than one letter) and not on the basis that ‘शी’ has ‘श्’ as a marker.

4. The अनुवृत्तिः of ‘प्रत्ययस्य’ comes into the सूत्रम् 1-3-8 लशक्वतद्धिते from the सूत्रम् 1-3-6 षः प्रत्ययस्य। Hence in order for 1-3-8 to apply in step 3, ‘शी’ would have to be a प्रत्ययः (affix). But ‘शी’ is a आदेशः (substitute) prescribed by the सूत्रम् 7-1-17 जसः शी, which is outside the प्रत्यय-अधिकारः (which runs from 3-1-1 प्रत्यय: to the end of the fifth chapter). Then, how does 1-3-8 apply in step 3? Hint: Consider the सूत्रम् 1-1-56 स्थानिवदादेशोऽनल्विधौ।
Answer: As per the सूत्रम् 1-1-56 स्थानिवदादेशोऽनल्विधौ – A substitute (आदेश:) is regarded as the item that it substituted (स्थानी) – except in the case of an operation which depends on a specific letter (अल्) of the स्थानी। Since the substitute ‘शी’ comes in place of ‘जस्’ which is a प्रत्ययः, once the substitution happens, ‘शी’ gets the designation प्रत्ययः and this allows सूत्रम् 1-3-8 लशक्वतद्धिते to apply.

5. In the affix ‘सुँ’, the letter ‘उँ’ is a ‘इत्’ letter. Why is the letter ‘ई’ in ‘शी’ not a ‘इत्’ letter?
Answer: As per the सूत्रम् 1-3-2 उपदेशेऽजनुनासिक इत् – The nasalized vowels are इत् in a उपदेशः (original enunciation). The letter ‘उँ’ in the affix ‘सुँ’ is nasalized, while the letter ‘ई’ in ‘शी’ is not. Therefore as per 1-3-2, the vowel ‘उँ’ in the affix ‘सुँ’ gets the designation ‘इत्’, while the letter ‘ई’ in ‘शी’ does not.

6. Why did we apply 6-1-87 आद्गुणः, instead of the rule 6-1-102 प्रथमयोः पूर्वसवर्णः in step 4?
Answer: The पूर्वसवर्णदीर्घः substitute (ordained by 6-1-102 प्रथमयोः पूर्वसवर्णः) is blocked by the सूत्रम् 6-1-104 नादिचि – The पूर्वसवर्णदीर्घः substitute (ordained by प्रथमयोः पूर्वसवर्णः 6-1-102) shall not take place when a letter of the इच्-प्रत्याहारः follows a अवर्ण: (long ‘आ’: or short ‘अ’)। In step 4, we have ‘अ’ (of ‘सर्व’) followed by ‘ई’ (a इच् letter), hence 6-1-104 blocks 6-1-102. Thus 6-1-87 आद्गुणः applies and we get the final form सर्वे।