Who knows how “Salve Sancta Parens” was translated into English from the original Latin Language to use as text for the English intro it antiphon in SEP?
If you mean, “what is the source of the translation?”, the texts of the SEP antiphons come from The Gregorian Missal Solesmes, 1990. The Gregorian Missal has since been revised to replace - where possible - its original translations with the translations in ICEL’s The Roman Missal, 3rd Edition. The original 1990 translations seem based upon Bible translations popular in English Catholicism.
Salve Sancta Parens is not a biblical text. It takes two lines of the "Carmen" (II, 63-64) of Sedulius a Christian poet of the fifth century, it serves as the Introit in the Masses of the Blessed Virgin, more here, https://www.newadvent.org/cathen/13680a.htm
To participate in the discussions on Catholic church music, sign in or register as a forum member, The forum is a project of the Church Music Association of America.