@ashok#Explanation of परस्मैपदी and आत्मनेपदी in Day 24 video.
In searching the dictionary we find verbs that end with ति and some verbs end with ते. Words ending with ति and ते represent present tense verbs forms and there is no difference in the meaning. However, we cannot say लिखते or वन्दित. We must say लिखति and वन्दते only. Verb forms ending with ति are called परस्मैपदी words. Verbs ending with ते are called आत्मनेपदी verbs.
However, certain verbs can be used as परस्मैपदी as well as आत्मनेपदी verbs. Such verbs are said to be उभयपदी. For example, पचति and पचते, करोति and कुरूते, क्रीणाति and क्रीणीते. What is the rule for using which verb form for उभयपदी verbs? That is when is it appropriate to use पचति and when is it appropriate to use पचते? If the effect of action (क्रिया फल) goes to somebody else then we have to use परस्मैपदी verb. If the effect the verb is returned to doer of the action then we have to use आत्मनेपदी verb form. For example, mother cooks for somebody else including herself then we have to परस्मैपदी. Mother cooks food which is eaten by others as well as herself would be - माता पचति . If mother cooks for herself and eats then we to use आत्मनेपदी - माता पचते . Similarly, क्रीणाति would be used if one is buying for others and oneself, क्रीणीते would be used if one is buying for oneself.
Hope this summary of Day 24 video helps others.