The final ā of a bha aṅga (stem) is elided when it ends in a root.,
Thus कीलालपः पश्य, कीलालपा, कीलालपे, शुभंयः पश्य, शुभंया, and शुभंये from कीलालपा and शुभंया ॥ Why do we say 'the आ of a root'? Observe खट्वाः पश्य, मालाः पश्य ॥ This sutra should be divided into two (1) आतः (2) धातोः; so that the long आ in general may be elided. For Panini himself has declined क्त्वा and श्ना by the elision of आ, see (VII. I. 37), (क्त्वो ल्यप्) and (III. I. 83), (श्नः शानच्) ॥,