There are two genders in Swedish, en words (common) and ett words (neuter). Bok is an en-word, so it uses the indefinite article en as opposed to ett.
Swedish sounds so soft. "en" sounded really quiet. and the word "bok" sounds so beautifully crafted to me. so soft it sounds
When i first heard this... I thought the bot was saying "En och"... Which had me so confused haha.