Official English text from the Liturgy of the Hours:
O Flower of Jesse’s stem, you have been raised up as a sign for all peoples; kings stand silent in your presence; the nations bow down in worship before you. Come, let nothing keep you from coming to our aid.
Official Latin text:
O Radix Jesse, qui stas in signum populorum, super quem continebunt reges os suum, quem gentes deprecabuntur: veni ad liberandum nos, iam noli tardare.
More literal English translation:
O Root of Jesse, that stands as a sign for the people, before whom the kings keep silence and unto whom the Gentiles shall make supplication: come, to deliver us, and tarry not.