Why do English-speaking Catholics say 'descended into hell' instead of 'descended into Hades' or 'into Sheol'?

Why do English-speaking Catholics say “descended into hell” instead of “descended into Hades” or “into Sheol“?

It is simply a matter of a bad translation from the Latin word for inferus.

The original Latin goes as such: ”descendit ad inferos” in the Apostles’ Creed.

Inferus has normally been translated as the lower regions or the netherworld.

Infernus

Etymology

From Proto-Italic *enðeros, from Proto-Indo-European *h₁n̥dʰér-o-s, from *h₁n̥dʰér. Cognate with English under, Sanskrit अधर (ádhara). *ð>f is irregular in word-internal position and is either explained as (Faliscan) dialectal influence or by assuming metanalysis as a compound with in.

Adjective

īnferus (feminine īnfera, neuter īnferum, comparative īnferior, superlative īnfimus or īmus); first/second-declension adjective

1. low

2. (in the masculine plural) the souls of the dead

3. (in the neuter plural) the netherworld, the underworld, Hell

References

• inferus in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press

• inferus in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers

• inferus in Gaffiot, Félix (1934) Dictionnaire illustré Latin-Français, Hachette

• Carl Meissner; Henry William Auden (1894) Latin Phrase-Book‎1, London: Macmillan and Co.

  • (ambiguous) the gods of the upper, lower world: super; inferi

  • (ambiguous) the world below: inferi (Orcus and Tartarus only poetical)

  • (ambiguous) to descend to the world below: ad inferos descendere

  • (ambiguous) to be in the lower world: apud inferos ease

The fact is the phrase just up to very recently employed the word dead for the Latin word inferus. This is a practice I still follow as I believe it is more faithful to the Latin translation.

Roman Catholic Church

The initial (1970) English official translation of the Roman Missal of the Roman Catholic Church adopted the ICET version, as did catechetical texts such as the Catechism of the Catholic Church.

I believe in God, the Father almighty, creator of heaven and earth. I believe in Jesus Christ, his only Son, our Lord. He was conceived by the power of the Holy Spirit and born of the virgin Mary. He suffered under Pontius Pilate, was crucified, died, and was buried. He descended to the dead. On the third day he rose again. He ascended into heaven, and is seated at the right hand of the Father. He will come again to judge the living and the dead. I believe in the Holy Spirit, the holy catholic Church, the communion of the saints, the forgiveness of sins, the resurrection of the body, and the life everlasting. Amen.

In 2008 the Catholic Church published a new English translation of the texts of the Mass of the Roman Rite, use of which came into force at the end of 2011. It included the following translation of the Apostles' Creed:

I believe in God, the Father almighty, Creator of heaven and earth, and in Jesus Christ, his only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary, suffered under Pontius Pilate, was crucified, died and was buried; he descended into hell; on the third day he rose again from the dead; he ascended into heaven, and is seated at the right hand of God the Father almighty; from there he will come to judge the living and the dead. I believe in the Holy Spirit, the holy catholic Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting. Amen.

Apostles' Creed (Wikipedia)

A new translation of the Mass of the Ordinary Form was inaugurated on the First Sunday of Advent in 2011. Surprisingly enough the Apostles’ Creed was overlooked!

The New Mass: Continuities and Changes The changes (and their continuities with the older form of the Mass) are obvious from the first time the priest says, "The Lord be with you." In place of the familiar "And also with you," the congregation responds, "And with your spirit"—a literal translation of the Latin "Et cum spiritu tuo," found in both forms of the Mass. The Confiteor (the penitential rite), the Gloria ("Glory to God in the highest"), the Nicene Creed, and the dialogue between the priest and the congregation after the Agnus Dei ("The Lamb of God") and immediately before Communion all hark back to the older form of Mass—as well they should, because both forms of the Mass share the same Latin text for these parts.

Still, it would be a mistake to think that the new translation significantly alters the Novus Ordo. The changes put in place by Pope Paul VI in 1969 remain, as do all of the major differences between the Traditional Latin Mass and the Novus Ordo. All the new translation does is to tighten up some very loose translations of the Latin text, restore a certain dignity to the English text of the Mass, and reinstate a few lines at various points in the Mass that had simply been dropped in the earlier translation from Latin to English. - The New Translation of the Catholic Mass

We may yet need a fourth revision of its’ texts!