听隔壁有人唱歌。翻译成英文。

i head sb singing next door

你的句子没有标点，所以可以有两句理解。

听！隔壁有人唱歌。
listen! someone is singing next door.

听见隔壁有人唱歌。
i hear someone is singing next door.

意思也差不太多，都表示，现在正有人在唱歌。

Listen!there is somebody singing in the next room

Listen！ Someone's singing in the next room.

Listen！ Someone is singing in the next room.

Listen！ Someone's singing in the next door.