With this act, I have to say, "Pope Francis, what an amazing pope! No pope in the history of the Church has done such a thing!" Oh... wait... never mind (Sorry, I couldn't resist being sarcastic). It seems that St. Joseph's name was added to the ancient Roman Canon (a.k.a., Eucharistic Prayer I) by Bl. Pope John XXIII in 1962, when the last reform of the sacred liturgy prior to the Second Vatican Ecumenical Council was made- there was only one Eucharistic Prayer in the Latin liturgy prior the reform. When celebrated in the Extraordinary Form, Holy Mass is sung(/said) according to the 1962 Missale Romanum.
It still bears noting that Pope Francis delayed his installation as Bishop of Rome by a few days so that it would be held on the Solemnity of St. Joseph, probably not least of which because, among other things (like the dying, demons, etc.), St. Joseph is the Patron of Italy.
This change will not go into effect in the Ordinary Form celebrated in English until the Congregation for Divine Worship provides an approved translation, or a translation undertaken by the English-speaking conferences of bishops submit a translation to and it is approved by the same Congregation. The decree seems to indicate that the Congregation will issue an approved translation in English.
Fr. Z, over at his blog, which began life as "What Does the Prayer Really Say," as is his wont, offers very credible translations, which I cite below:
Eucharistic Prayer II: "that with the Blessed Virgin Mary, Mother of God, with Blessed Joseph, her Spouse, with the blessed Apostles"
Eucharistic Prayer III: "with the Most Blessed Virgin Mary, Mother of God, with blessed St. Joseph, her Spouse, and with your blessed Apostles and glorious Martyrs"
Eucharistic Prayer IV (the one that virtually nobody uses, ever): "with the Blessed Virgin Mary, Mother of God with blessed Joseph, her Spouse, and with your Apostles"
I love the way the Congregation began this marvelous decree: "Exercising his paternal care over Jesus, Saint Joseph of Nazareth, set over the Lord’s family, marvelously fulfilled the office he received by grace. Adhering firmly to the mystery of God’s design of salvation in its very beginnings, he stands as an exemplary model of the kindness and humility that the Christian faith raises to a great destiny, and demonstrates the ordinary and simple virtues necessary for men to be good and genuine followers of Christ. Through these virtues, this Just man, caring most lovingly for the Mother of God and happily dedicating himself to the upbringing of Jesus Christ, was placed as guardian over God the Father’s most precious treasures. Therefore he has been the subject of assiduous devotion on the part of the People of God throughout the centuries, as the support of that mystical body, which is the Church."
Sancte Ioseph, ora pro nobis!