The affix akac (ak) is added to an indeclinable and to a Pronominal before the last vowel of those words in the sense of prāgrīva affixes.,
The च् shows that the acute accent falls on the final 6.1.163, though the affix is inserted in the middle of the word. The phrase तिङश्च 5.3.56 is understood here also. This अकच् debars क ॥ Thus उच्चैः + अक् = उच्च् + अक् + ऐः = उच्च॒॒कैः; similarly नीच॒॒कैः, शमकैः from नीचैः and शनैः ॥ So also after Pronominals, as सर्वके, विश्वके and उभयके from सर्वे, विश्वे and उभये ॥ In these last examples, it will be seen that the affix is added to सुबन्त words i.e. to declined nouns, and not to प्रातिपदिक or crude-noun: as was required by 4.1.1. Sometimes, however, the affix is added after a Pratipadika also. The usage will determine when the affix should be added to a Nominal stem (Pratipadika) and when to a Subanta word. Thus in युष्मकाभिः, अस्मकाभिः, युष्मकासु, अस्मकासु, युवकयोः, आवकयोः, the affix is added to pratipadika viz to युष्मद्, अस्मद्, giving युष्मकद्, अस्मकद् which are then declined as Pronominals. But in the examples त्वयका, मयका त्वयकि, मयकि, the affix अक् is added to the त्वया, मया (the Instrumental case of युष्मद् and अस्मद्), and त्वयि and मयि the Locative singular of the same. From the above examples, this rule may be deduced; the affix अक् is added to the Pradipadika, when case-affixes beginning with ओ, स or भ follows; and the affix is added to the declined pronoun, in the remaining cases.
Vart:- The affix काम् is added to the Indeclinable तूष्णीम् ॥ The म् is indicatory, therefore, का comes before the final vowel (1. 1.47). As तूष्णीम् + का = तूष्णीकाम्, as तूष्णीकामास्ते, तूष्णीकां तिष्ठति 'he remained silent'. When, however, the meaning in that 'whose habit is so', then the affix क is added, and the म् of तूष्णीम् is elided. As तूष्णीकः 'a taciturn'.
The phrase तिङश्च 5.3.56 being understood here, the affix अक् comes after finite verbs also. As पचति-पचतकि, जल्पति-जल्पतकि ॥,