The gerund is used to generate the meaning "having done X".
It is an indeclinable participle, meaning that it acts as an adverb
modifying the main verb of the sentence.
Many roots require the insertion of an "इ" before
adding the "-त्वा".
Roots of the 10th गण (ex: चिन्त्) form the gerund using their present stem, replacing the final "-अ" with "-इ" before adding the ending.
↓
+
+
त्वा
=
(weakened root)
(suffix)
(gerund)
Select a Root:
Root with उपसर्ग (prefix)
(root)
Notes
For roots with upasargas, use the lyabanta construction.
Add "-य" to the weakened form of the verb root
(resembling the PPP).
An additional "त्" is inserted when the weakened root
ends in a short vowel.
Some roots ending in "-अम्" or "-अन्" may optionally take
either "-य" or "-त्य" ending.