In English, gerunds are made by adding -ing to the end of a verb: "(the) singing."
To make a gerund, add -d to A-verbs and -ed to I-verbs.
Linna- sing → Linnad singing
(n)Dag- kill → Daged killing
A gerund is a very noun-like verb. A gerund can take on objects and adverbs like a verb, but it can't have a subject. It takes the place of infinitives in Sindarin grammar.
In yrch anírar daged 'elaidh. - The orcs want to kill trees.
When the gerund acts on an accusative pronoun, the pronoun goes beside it like it was any other verb. It does not go before the active verb.
In yrch anírar gi ndaged. - The orcs want to kill you.
When the gerund is used as a noun, it can't be made plural, but otherwise it acts as though it is a normal noun and undergoes mutation.
Daro i naged. - Stop the killing.