There are official hymns in the Latin Liturgy of the Hours, but we don't get to see them, or at least not very many of them, in our Christian Prayer breviaries. However, the Mundelein Psalter, a one volume breviary of Morning, Evening and Night Prayer from Liturgy Training Publications of Chicago, does contain these hymns in both Latin and English. I've already posted about this here and also here.
Here is an excerpt from the hymn for Morning Prayer, feast of the Presentation:
Come, Prophet far advanced in years,
Make known to all your joy fulfilled,
Show unto us the Infant Christ,
The Light for all the world to see.
The Temple gates admit the Babe,
The truest Temple of the Lord,
His happy parents gladly come
To keep the Law that He transcends.
O Mary, to the Father bring
His only Son, your little One,
And offer him the Victim pure,
The price with which we are redeemed.
