"I am the man."
Translation:Jeg er manden.
The -en and -et endings are added when in English we would use the word "the" without an adjective between "the" and the noun. For example:
et æble = an apple, but æblet = the apple, but det grønne æble = the green apple
en mand = a man, but manden = the man, but den lille mand = the little man