This is the 816th most frequent Icelandic word.
einhverjum
The Icelandic word "einhverjum" is the dative singular form of "einhver," meaning "someone" or "some" in English.
In this sentence, 'einhverjum' is the dative case of 'einhver', meaning 'someone' or 'anyone', and is used because the verb 'segja' (to tell) governs the dative case.
Ég sagði einhverjum frá þessu.
I told someone about this.
Here, 'einhverjum' is again in dative case as it follows the preposition 'frá', which requires the dative case, referring to an unidentified individual.
Við fengum hjálp frá einhverjum sem við þekkjum ekki.
We received help from someone we don’t know.
In this instance, 'einhverjum' is dative as the impersonal construction implies an experiencer in the dative case.