The song is about being grateful to God for all of the gifts he gave the Jewish people, such as taking them out of slavery, giving them the Torah and Shabbat, and had God only given one of the gifts, it would have still been enough. This is to show much greater appreciation for all of them as a whole.

Dayenu

Ilu ho-tsi, ho-tsi-a-nu, 
Ho-tsi-a-nu mi-Mitz-ra-yim, 
Ho-tsi-a-nu mi-Mitz-ra-yim, 
Da-ye-nu!

.. CHORUS: 
.. Dai, da-ye-nu, 
.. Dai, da-ye-nu, 
.. Dai, da-ye-nu, 
.. Da-ye-nu, da-ye-nu, da-ye-nu! 
.. 
.. Dai, da-ye-nu, 
.. Dai, da-ye-nu, 
.. Dai, da-ye-nu, 
.. Da-ye-nu, da-ye-nu!

Ilu na-tan, na-tan la-nu, 
Na-tan la-nu et-ha-Sha-bat, 
Na-tan la-nu et-ha-Sha-bat, 
Da-ye-nu!

.. (CHORUS)

Ilu na-tan, na-tan la-nu, 
Na-tan la-nu et-ha-To-rah, 
Na-tan la-nu et-ha-To-rah, 
Da-ye-nu!

.. (CHORUS) 

(A singable English version:)

Had He brought all, brought all of us, brought all of us 
out from Egypt, 
then it would have been enough. Oh, dayenu.

Chorus: 
Da-da-yeinu_____, da-da-yeinu_____, da-da-yeinu_____, 
dayeinu, dayeinu, dayeinu.

(repeat)

Had He given, given to us, given to us all the Sabbath, 
then it would have been enough. Oh, dayenu.

Chorus

Had He given, given to us, given to us all the Torah, 
then it would have been enough. Oh, dayenu.

Chorus