न पदान्तद्विर्वचनवरेयलोपस्वरसवर्णानुस्वारदीर्घजश्चर्विधिषु

This sutra lays down an exception to the previous sutra, by which it was ruled that an adesa which replaced a vowel becomes sthanivat under certain conditions. This sutra says that a vowel adesa is not sthanivat under the following circumtances.

1. पदान्तविधिः-- 'A rule relating to the last letter of a word.' Thus the अ of अस् is elided before the terminations of dual and plural numbers (VI. 4. III). Thus we have अस्ति 'he is,' स्तः 'they two are,' सन्ति 'they are.' Now in the technical phraseology of Sanskrit grammarians, the अ of स्तः and सन्ति is replaced by an adesa called लोप्, the peculiarity of which is that the whole of it vanishes. So that before the word स्तः there is this adesa existing, though it is in an invisible form. This invisible adesa will be sthanivat, as it replaces a vowel, by reason of something that follows, i. e. the affixes तः and अन्ति being ङित् 1.2.4; and it will have all the powers of अ by the last sutra, in the absence of any rule to the contrary. Therefore, in the sentence कौ स्तः 'who two are' the final औ of कौ and the invisible अ of स्तः ought to coalesce by rules of sandhi into आव 6.1.78. But this incongruity is prevented by the present sutra, by which the change of औ into आव् is a पदान्त विधि or a rule relating to the finals of a word, therefore, we have कौ स्तः । So also in तानि सन्ति, rule 6.1.77 is not applied.

2. द्विर्वचनविधिः 'a rule relating to the doubling of letters.' In the sandhi of दधि + अत्र we have दध्यत्र. Here इ is changed into य्. If this य् were sthanivat to इ, then the rule by which ध् could be doubled before य् would be inapplicable. But य् is not equivalent to इ, though its substitute; and we have the doubling of ध् and get the form दद्ध्यत्र. Therefore, in rules relating to the doubling of letters the adesa is not equivalent to the sthani.

3. वरेविधिः 'a rule relating to the affix वरच्.' The affix वरच् is a krit affix which is added to certain roots to form nouns of agency; thus from ईश् 'to rule' we have ईश्वरः 'ruler.' So from the intensive verb यायाय we have यायावरः 'a vagrant.' It is formed in this wise यायाय + वर 3.2.176 = यायाय् + ० + वर 6.4.48. Here the अ of य has been dropped and replaced by lopa, on account of its being followed by the ardhadhatuka affix वरच्. The next step is to drop the य् by rule 6.1.66 which declares that the letters व् and य् are dropped before affixes beginning with any consonant except i. e., beginning with consonants of वल् pratyahara. Thus याया + ० + वर. Now there is a rule 6.4.64 which declares that the final long आ of a base is dropped before ardhadhatuka affixes having an initial vowel. Here therefore, if the adesa 'lopa,' which replaced the vowel अ, be considered as sthanivat, and be considered as an affix having a latent initial vowel, then the आ of याया requires to be dropped. But this sutra prevents this and we have the form यायावर; as, अप्सु यायावरः प्रवपेत पिण्डान् ॥

4. यलोपविधिः 'a rule relating to the dropping of ya.' Thus there is a verb कण्डूय 'to scratch'. In forming an abstract noun from it, the affix ति (tech. क्तिच्) is added. Thus कण्डूय + ति = कण्डूय् + ० + ति, the अ of य being dropped by 6.4.48. Now there is a rule 6.1.66 already mentioned above which requires the elision of य् before consonantal affixes. Now if the lopa substitute be considered as sthanivat to अ, then the affix ति is not an affix having an initial consonant and the rule, which requires the dropping of य्, would not apply. The present sutra, however, provides for this, and we have the form कण्डूतिः 'scratching.'

5. स्वरविधिः 'a rule relating to accent.' There is a sutra 6.1.193 which says that when a word is formed by an affix that has an indicatory ल्, the vowel that immediately precedes such an affix has the udatta accent. Now ण्वुल् is an affix that has an indicatory ल्, the real affix bein अक (VII. I. I.). It is an affix used in forming nouns of agency. Adding this affix to the desiderative verb चिकीर्ष 'desirous of doing' we have:-- चिकीर्ष + अक = चिकीर्ष् + ० + अक, the अ being dropped by 6.4.48. Now if the zero be considered as sthanivat, then the accent must fall on this latent अ but it is not so. The accent falls on the ई of की; and we have चि॒॒कीर्ष॑कः, so also जि॒॒हीर्ष॑कः ॥

6. सवर्णविधिः 'a rule relating to the substitution of homogeneous letters.' To explain this, let us form the second person singular of the verb शिष् in the imperative mood. The affix हि is the sign of the second person imperative singular; and the verb शिष् belongs to the seventh-class of verbs called Rudhadi. This class of verbs take the vikarana श्नम् 3.1.78 the श् and म् being indicatory the real affix is न. This न is inserted between the radical vowel and the final consonant 1.1.47. Therefore we have the following equation:- शिष् + श्नम् + हि = शि + न + ष् + हि = शि + न् + ० + ष् + हि. The अ of न is dropped by (VI. 4. III), which declares that the अ of श्नम् is dropped before those sarvadhatuka terminations which are कित् or ङित्. By 1.2.4 all sarvadhatuka terminations which have not got an indicatory प् are considered as ङित्. The affix हि therefore is a ङित् sarvadhatuka affix, and by rule 3.4.87, हि is to be regarded as अपित्, not having an indicatory प्. The next stage is :-- शि + न् + ० + ष् + धि; the हि being changed into धि by rule 6.4.101 which says that 'हि is changed into धि, when it follows a root which ends in a consonant of झल् pratyahara:' here ष् and ध् are changed by general rules of sandhi into ड् and ढ् and we have शि + न् + ० + ड् + ढि 8.4.41. Then there is a rule 8.3.24, which says that in the body of a word the 'न् is changed into anusvara when followed by a consonant of झल् pratyahara.' Therefore we have :-- शि + ० + ० + ड् + ढि. This is the form to which the present rule is applicable. Thus, there is a rule 8.4.58 which says that an anusvara followed by a letter of यय् pratyahara i.e., any consonant except ह्, श् ष् and स् is changed into a letter homogeneous or savarna to the letter that follows. Therefore, if we regard zero as sthanivat to the अ which it replaces, the anusvara cannot be changed into ण् as homogeneous to ङ्. But it is not to be so regarded, and we have the form शि + ण् + ड् + ढि = शिण्ड्ढि or शिण्ढि; so also पिण्ढि.

7. अनुस्वारविधिः 'a rule relating to anusvara.' The above example will serve the purpose here:-- शि + न् + ० + ड् + ढि. This by the rule already mentioned 8.3.24, requires the न् to be changed into anusvara. Now if zero be considered as sthanivat, then न् is not followed by a letter of झल् pratyahara , and cannot be changed into anusvara. However, the zero is not regarded as sthanivat, and we change the न् into anusvara. Other examples are शि + न् + ० + ष् + अन्ति = शिंषन्ति; so also पिंषन्ति ॥

8. दीर्घविधिः 'a rule directing the substitution of long vowels for short vowels.' Let us form the Inst. sing. of the noun प्रतिदिवन्. The termination of the Inst. sing. is टा or आ. Therefore, we have प्रतिदिवन् + आ = प्रतिदिव् + ० + न् + आ. Here the अ has been elided by rule 6.4.134, which teaches that words ending in अन् lose their अ before terminations technically called Bha. The termination of Inst. sing. is a Bha termination by force of rule 1.4.18. The next rule that now comes into operation, is 8.2.77, which requires the lengthening of the short penultimate vowels, of the इक् pratyahara, of words that end in र् or व् and are followed by a consonant. Here दिव् is a root that ends in व्; and if the zero be considered as sthanivat, then this व् is not followed by a consonant, but by a latent vowel, and so the short इ of दिव् will not be lengthened. This rule, however, provides for such lengthening, and therefore we have :- प्रतिदिव् + ० + न् + आ = प्रतिदीव्ना ॥

9. जश्विधिः 'a rule requiring the substitution of soft unaspirate consonants, of pratyahara जश्, in the place of hard consonants' In this case also the adesa that takes the place of a vowel is not sthanivat.

Let us add the affix क्तिन् to the root अद् 'to eat,' compounded with the word स or समान. In Vedic literature अद् is replaced by घस्, 2.4.39; so we have, स + घस् + क्तिन् = स + घस् + ति = स + घ् + ० + स् + ति 6.4.100 = स + घ् + ० + ० + ति 8.2.26 = स + घ् + ० + ० + धि 8.2.40.

It is at this stage, that rule 8.4.53 requires the घ् to be changed into ग्. This is a जश् rule, and teaches that in the place of letters of झल् class, the letters of जश् class are substituted, if followed by letters of झश् class. If the zero which was obtained by dropping the अ of घ, be considered as sthanivat, then the घ् is not followed by a consonant of झश् class, and cannot be changed into ग्. But it is not so. Therefore सघ् + ० + ० + धि = सग्धिः (Yaj. Ved. XVIII. 9). The various rules, by which first अ is omitted, and then स् is dropped, have been referred to in brackets, and will be explained in their proper places.

Similarly the word बब्धाम्, which is the Imperative (lot) 2nd per. dual of the root भस्, and is thus evolved. This root belongs to the Juhutyadi class, and therefore, there is reduplication. Thus भस् + ताम् = भस् + भस् + ताम् = भ + भस् + ताम् = ब + भस् + ताम् = ब + भ् + ० + स् + ताम् 6.4.100 = ब + भ्+ ० + ० + ताम् 8.2.26 = ब + भ् + ० + ० + धाम् 8.2.40 = ब + ब् + ० + ० + धाम् = बब्धाम् ॥ Here the change of भ् into ब् is by the application of 8.4.53, which is a jas rule, and therefore, the zero is not sthanivat.

10. चर्विधिः 'a rule requiring the substitution of the letters of चर् pratyahara instead of other consonants.' In the application of this rule, also the substitute that replaces a vowel is not sthanivat.

Let us form the 2nd pers. sing. perfect of the verb अद् 'to eat.' अद् is replaced by घस् 2.4.40 and अतुस् is the termination of the second person singular of lit or perfect tense. घस् + अतुस् = घस् + घस् + अतुस् 6.1.8 = घ + घस् + अतुस् 7.4.60 = ज + घस् + अतुस् 8.4.54 = ज + घ् + ० + स् + अतुस् 6.4.98 = जघ् + ० + सतुस्.

At this stage comes the चर् rule in operation, which says that the letters of झल् pratyahara are replaced by those of चर् pratyahara, when followed by letters of खर् pratyahara. Here घ् is a letter of झल् class, and if zero is not sthanivat, it is followed by स् which is a letter of खर् class, and therefore घ् is required to be changed into क् of चर् class. By the present rule, zero is not sthanivat and thus we have :- जक् + सतुस् = जक्षतुः 8.3.60.

Similarly अक्षन् the 3rd per. plural aorist of घस् is thus formed:- अ + घस् + च्लि + अन् = अ + घस् + अन् 2.4.80 = अ + घ् + ० + स् + अन् 6.4.98. Here had the lopa been sthanivat, rule 8.4.55 could not have applied. But it being a char rule, the lopa is not sthanivat. Therefore we have, अक्षन्.

When lopa is the substitute of a vowel, it is not sthanivat, for the purposes of the application of the rules of accent, rules relating to the doubling of letters, and the rules relating to the elision of ya. In other places, with the exception of the above three; the lopa substitute of a vowel is, and must be treated as sthanivat. Thus बहुखट्वकः, किर्योः, गिर्योः, वाय्वोः. In these cases the lopa-adesa being sthanivat, the rules relating to accent, lengthening and the elision of ya, do not apply.,