The Dutch do not make a difference between 'someone' and 'anyone'. They are both called _iemand_.
_Iemand_ and _niemand_ are singular pronouns.
Dutch | Application | English
iemand | singular | someone, anyone
niemand | singular | noone
Heb je het al aan iemand verteld? | Did you already tell anyone?
Ik heb het al aan iemand verteld. | I already told it to someone.
Nee, ik heb het nog aan niemand verteld. | No, I did not tell anyone yet.
Niemand mag het weten. | Noone is allowed to know.