And there is substitution of ā for the finals of mī 'to hurt', mi 'to scatter' and dī 'to decay' when the affix lyap follows, as well as before those affixes which demand this substitution for the diphthong.,
By force of the word च 'and' in the sutra, the substitution takes place of the diphthongs also of these verbs before all affixes other than शित्, and this substitution takes place, before the occasion for the applying of the affixes arises (उपदेशावस्थायाम् आत्वं भवति) ॥ So that these verbs should be understood as if they were enunciated with an आ, so that all rules of affixes relating to आ will apply to them. Thus प्रमाता, प्रमातव्यम्, प्रमातुम्, प्रमाय, निमाता, निमातुम्, निमातव्यम्, निमाय, उपदाता, उपदातव्यम्, उपदातुम्, उपदाय ॥ The substitution of आ being understood to have taken place in the very उपदेश (in the dhatupatha) of these roots, the affixes relating to roots ending in इ or ई do not apply to these at all. Thus उपदायो वर्त्तते, ईषदुपदानं, formed by घञ् and युच् by taking दी = दा and adding these affixes 3.3.128 and 3.3.18 and not the affixes अच् 3.3.56 and खल् 3.3.126.,