The affix yak comes after a root when a sārvadhātuka -- tiṅśitsārvadhātukam [[3.4.113]], follows, denoting the action or the object.,
In forming Impersonal and Passive verbs, this affix is employed in the conjugational tenses. Thus in Impersonal verbs आस्यते भवता 'you sit', शय्यते भवता 'you lie'. So in passive verbs; as क्रियते कटः and गम्यते ग्रामः. The क of यक् is servile, and prevents guna and vriddhi. This affix is also used in reflective voice (कर्म्मकर्त्तरि); as क्रियते कटः स्वयमेव 'the mat becomes made of itself'.,