Miserere mei, Deus - Allegri - Tenebrae

Psalm 51 Transliteration so you can actually follow along:

Miserere mei, Deus
Have mercy on me, God

Secundum magnam misericordiam tuam
According to your great kindness

Et secundum multitudinem miserationum tuarum
And according to the multitude of your mercies,

Dele iniquitatem meam
Erase my iniquities

Amplius lava me ab iniquitate mea
Wash me completely from my iniquities

Et a peccato meo munda me
And cleanse me of my sins

Quoniam iniquitatem meam ego cognosco
For I know my iniquities

Et peccatum meum contra me est semper
And my sins are always before me

Tibi soli peccavi
To you alone, I have sinned

Et malum coram te feci
And done evil before you

Ut iustificeris in sermonibus tuis
That you may be fair in your speech

Et vincas cum iudicaris
And justified in your judgement

Ecce enim in iniquitatibus conceptus sum
Behold, I was conceived in iniquity

Et in peccatis concepit me mater mea
And in sin did my mother conceived me

Ecce enim veritatem dilexisti incerta
Behold, you desire truth in the inward parts

Et occulta sapientiae tuae manifestasti mihi
And you teach me wisdom in the hidden places

Asparges me hysopo et mundabor
Purify me with hyssop and I will be clean

Lavabis me et super nivem dealbabor
Wash me, and I will be whiter than snow

Auditui meo dabis gaudium
Let me hear your joy and gladness

Et laetitiam exultabunt ossa humiliata
And my humble bones will rejoice

Averte faciem tuam a peccatis meis
Turn your face away from my sins

Et omnes iniquitates meas dele
And erase all of my iniquities

Cor mundum crea in me Deus
Create in me a pure heart, oh, God,

Et spiritum rectum innova in visceribus meis
And renew your right spirit within me

Ne proicias me a facie tua
Do not turn me away from your sight,

Et spiritum sanctum tuum ne auferas a me
And do not take your Holy Spirit from me

Redde mihi laetitiam salutaris tui
Return your gladness and salvation to me

Et spiritu principali confirma me
And uphold me with a willing spirit

Docebo iniquos vias tuas
I will teach sinners your way

Et impii ad te convertentur
And they will be converted unto you

Libera me de sanguinibus
Save me from blood,

Deus, Deus salutis meae
God, God of my salvation

Exultabit lingua mea iustitiam tuam
My tongue will praise of your righteousness

Domine labia mea aperies
Lord, open my lips

Et os meum adnuntiabit laudem tuam
And my mouth will sing your glory

Quoniam si voluisses sacrificium dedissem utique
Because you have not desired sacrifices

Holocaustis non delectaberis
For you don't delight in sacrifices, or I would do so

Sacrificium Deo spiritus contribulatus
Nor do you desire burnt offerings

Cor contritum et humiliatum
The sacrifices of God are a broken spirit
A broken and humble heart

Deus non spernet
God will not despise

Benigne fac Domine in bona voluntate tua Sion
Do well before the Lord in your good pleasure to Zion

Et aedificentur muri Hierusalem
And build the walls of Jerusalem

Tunc acceptabis sacrificium iustitiae
Then you accept the sacrifices of righteousness

oblationes et holocausta
In oblations and burnt offerings

Tunc inponent super altare tuum vitulos.
Then they will offer bulls on your altar.