In Episode 15 of Cosmic Monopole (Volume 1 of Time Crystal), Marianne sings a song to Catriona as they wait for Alex Karolyi to bring the doctor down to Marianne in the underground ATLAS cavern. The melody was written by Johann Friedrich Reichardt in 1781 to German words which are much older:

Schlaf, Kindlein, schlaf,
Der Vater hüt die Schaf,
Die Mutter schüttelts Bäumelein,
Da fällt herab ein Träumelein.
Schlaf, Kindlein, schlaf!

Marianne learnt this lullaby from her German grandmother, who translated it from German into French.

Dors, bébé, dors,
Papa te garde encore,
Maman secoue les brindillettes,
Dans tes yeux tombe une somnollette,
Dors, bébé, dors.

This is the song Marianne sings to Catriona. Here is Wyken Seagrave’s attempt at singing the song, although he sings an octave lower than Marianne!

Marianne then translates it into English:

Sleep, baby, sleep.
Your father guards the sheep.
Your mother shakes the branches high,
A dream falls gently in your eye.
Sleep, baby, sleep.