Ah, Wikipedia!
The boar's head in hand bring I, (Or: The boar's head in hand bear I,)
Bedeck'd with bays and rosemary.
I pray you, my masters, be merry (Or: And I pray you, my masters, merry be)
Quot estis in convivio (Translation: As many as are in the feast)

CHORUS
Caput apri defero (Translation: The boar's head I offer)
Reddens laudes Domino (Translation: Giving praises to the Lord)

The boar's head, as I understand,
Is the rarest dish in all this land,
Which thus bedeck'd with a gay garland
Let us servire cantico. (Translation: Let us serve with a song)

CHORUS

Our steward hath provided this
In honour of the King of Bliss;
Which, on this day to be served is
In Reginensi atrio. (Translation: In the Queen's hall)

CHORUS