27. The isolating stage of Indus did not distinguish tenses or moods by forms. The same bare verb stood for all tenses and moods in all persons and numbers of the subject. The tense or mood was clear just from the context. For example, ha = I say, you said, he will say, let him say, and so on.

28. Later, at the agglutinative stage, the past tense began to be distinguished by the syllable A prefixed to the verb. Thus A-ha (past-say) = said, A-Sa (past-be) = there was, for all persons and numbers of the subject. At this stage, the affix gha was used for the future and ga was used for order, but their traces later are very thin and doubtful. Though gha could come down to the Vedic language in a very disguised form, ga can be seen even now in some rustic dialects of Hindi. As a matter of fact, there was also ha for the present perfect and ra for the past perfect in the spoken form of Indus, and they are still continuing in the rustic dialects of Hindi, but they are not traceable in Sanskrit, except through obscure reflexes.

a. When it became necessary to distinguish, at least, the persons, the distinction was carried out by suffixing -ta for the third person, -sa for the second person, and -ma for the first person. Thus the following extended forms emerged:

3. a-gA-ta

2. a-gA-sa

1. a-gA-ma

29. When the persons were distinguished in the past tense, the same process was carried out in the present tense by a slight bending:

                    3. yA-ti       gA-ti

                    2. yA-si       gA-si

                    1. yA-mi      gA-mi

30. Because the concept of plurality was already expressed through -Sa in the case system, the same was transferred to the tense mechanism. But then the sg. form was slightly bent towards u:

                    sg.          pl.

                    Aha        Ahu-Sa

                    ASa        ASu-Sa

a. In the extended past verbal form in 3p., the distinctive ending is eliminated:

3. a-gA-ta                 a-gu-Sa

b. The pl. of the present tense was distinguished otherwise in 3p. Here another sound -n- was employed. Thus

                    3. yA-ti                      yA-n-ti

(i) In the first person, -mi was extended by -si, but then the preceding mi was reverted to ma. Thus the extended pl. ending in the first person was -masi:

                    1. yA-mi                     yA-masi

c. The second person used to be much behind in this process. The pl. variety of -si was rather arbitrarily conceived to be -tha:

                    2. yA-si                       yA-tha

31. There was a slight bending towards u for expressing order in 3p.

                   3. yA-tu                        yA-n-tu

This order form is called imperative.

a. The second person was conceived through -dhi, which was later reduced to -hi :

          2. ga-dhi                       ga-hi

b. Its pl. form was conceived by -ta:

                    2. yA-hi                         yA-ta

32. Later, the monosyllabic verbs began to be extended by different syllables to convey specific ideas. The extending syllables were mostly the semivowels and the nasals ma and na, though even other syllables came for extension.

a. Among them -cha was conceived as a modal affix by the Sanskrit grammarians. Thus ga was extended by ma and -cha before the affixes were added:

3p. Present	ga-cha-ti	ga-cha-nti
Past	a-gama-ta	a-gama-nta
Imperative	ga-cha-tu	ga-cha-ntu

33. When the past tense forms began to be distinguished by ending, the prefix A was often ignored. One such example is available in Ait Up.: sa IkSata (he desired). This Upanisadic form is as old as the agglutinative stage of the Indus language.

This was the state of the Indus language by the end of the agglutinative stage.

34. At certain milestone after this stage, the language became accented and the size of the verbal forms began to be reduced. Because the past affix Ù bore the accent, the suffix elements at the end, namely 3. -ta 2. -sa 1. -ma lost their final a. Then the prefix A also was shortened to á. The forms of gA are the following:

                            3. á-gA-t

                            2. á-gA-s

                            1. á-gA-m

a. Even the pl. -sa lost its a. Thus there was 3. á-gu-s. Then the pl. in 2p and 3p were distinguished by -ta and -ma, when their memory as belonging to sg. faded:

                            sg.                                       pl.

                            3. á-gA-t                             á-gu-s

                            2. á-gA-s                             á-gA-ta

                            1. á-gA-m                            á-gA-ma

b. This reduction operated even in the pl. affix -n-ta, which was attached to bisyllabic verbs: 3p. pl. á-gama-nt á-gacha-nt

(i) The final t was ultimately lost in Sanskrit, but it used to appear in certain sandhi conditions.

35. The Indus language had reached the inflexional stage.

It was here that the agglutinative form pra-cha-ti was reduced to pR-chá-ti due to accent on cha. Similarly, ra-cha-ti was reduced to R-chá-ti. The syllable -cha-bore accent because it was an affricate, a consonant-cluster. This was not the case with -ma- and others.

36. At the inflexional stage of Indus, the accented past prefix á- was lost to convey some kind of injunction:

                            3. gAt

                            2. gAs

                            1. gAm

These are the injunctive forms of the Vedic grammar. They are generally used with the prohibitive particle mA (not, do not).

37. Some time later these injunctive forms were often strengthened by lengthening the last vowel of the forms:

                            3. gachAt

                            2. gachAs

But in the first person the final m was lost:

                            1. gachA

a. These strengthened forms were later called subjunctive, often supplemented by the full endings 3. -ti 2. -si:

                            3. gachAti

                            2. gachAsi

b. In the first person the original -mi was changed into -ni:

                            1. gachAni   gamAni   gAni

c. In pl. the past endings were retained:

                            3. gachAn

                            2. gachAta

                            1. gachAma gamAma

38. The same injunctive forms were further distinguished by inserting a syllable -yA- between the base and the past endings:

                            3. bhU-yA-t

                            2. bhU-yA-s

                            1. bhU-yA-m

These were the optative forms.

a. This -yA- also contracted to -I- after the a- base.

39. The pl. ending in the past tense for the third person had come from two sources: from Ahus Asus -us had been identified as the pl. ending, and from ágaman, etc. –an was identified as the pl. ending. Both -us and -an play their part in Sanskrit conjugation. However, -us merged with yA as -yus.

40. At the isolating stage itself we find that some verbs are reduplicated to express the intensification of the verbal idea: dha dha (it shines brightly).

a. At the agglutinative stage, when the persons were
first of all distinguished, dha-dha-ti appeared, probably as the pl. form. Then its sg. form was distinguished as dha-dhA-ti. On this pattern the whole set of the reduplicated forms evolved:

                    3. dhadhAti                      dhadhati

                    2. dhadhAsi –

                    1. dhadhAmi –

b. In 2p. and 1p. pl. the radical a was lost:

2. dhadh-tha

1. dhadh-masi.

Later the initial syllable was deaspirated, except in 2p pl. in which the second dh was deaspirated and devoiced due to the following voiceless and aspirate -tha. Therefore the forms are:

2. dhat-tha 

1. dadh-masi.

41. The Indus verb tan (to expand), deduced from tánas (offspring) from the Indus clause tanaSa (from the womb gems come out), had a wonderful population of forms.

a. It was extened to tan-o-ti and gave birth to tan-class in the Vedic grammar.

b. Then -no- was taken from it and added to some other verbs, making forms like su-no-ti, etc. This gave birth to su-class in the Vedic grammar.

c. The same tan was also extened to tan-A, but this base itself could not endure. However, some parasitic bases, taking -nA from it, gave birth to krI- class in the Vedic grammar.

d.The -n(a)- element from these forms themselves
was inserted in the middle of some verbs ending with consonants : ru-na-dh ru-n-dh from rudh, and so on. They formed the rudh- class in the Vedic grammar.

42. At the agglutinative stage of Indus itself, an affix -Tha had begun to serve for the past tense. There is a very doubtful example in the extant texts, when this Tha makes a past form with Sa (Sa-Tha = be-past), which is perhaps available in the contracted form S-Tha (be-past = there was) in the RV (7,103,7c). This S-Tha was later dentalised and deaspirated as *s-tá, but it never appears thereafter till in Hindi as thA  (there was).

This is perhaps a single agglutinative form traceable in the inflexional Vedic. This STha cannot otherwise be explained through the Vedic grammar.

a. The past suffix -tá, however, is the leading suffix in the whole history of the Sanskrit language.

43. Just as the imperative 2p. sg. ending -dhi was weakened to -hi, even 1p. pl. ending -masi was later reduced to -mas. Thus

                    yA-masi         yA-mas

                    dadh-masi      dadh-mas