This is the 24th most frequent Icelandic word.
ég
"I" (first-person singular pronoun).
In this sentence, 'ég' functions as the first person singular subject pronoun of the verb 'to be'.
Ég er að læra íslensku.
I am learning Icelandic.
Here, 'ég' is the grammatical subject in the active voice construction, denoting the doer of the action, which is to read.
Ég hef lesið þessa bók.
I have read this book.
In this case, 'ég' indicates the speaker as the person expressing necessity or intention to act.