The annunciation scene that shows up this week is from a 14th-century manuscript, and one of its most distinctive features is the banner displaying the words "Ave Maria," "Hail Mary."
The word "Ave" is the first word spoken by the angel Gabriel when he visits Mary, yet he does not actually say to her "Hail Mary." In the gospel of Luke in the Latin Vulgate version, he says: ave gratia plena Dominus tecum benedicta tu in mulieribus, "Hail, full of grace! Blessed are you among women."
During the Middle Ages, a Latin prayer became increasingly popular which is based on this passage from Luke: Ave Maria, gratia plena, dominus tecum, "Hail Mary, full of grace, the lord is with you." You can read more about the Ave Maria prayer at wikipedia, along with information about the use of rosary beads in conjunction with this prayer.
Another lovely feature of this particular annunciation scene is the way that a dove has descended from heaven, and can be seen next to Mary, right by her ear. This is very creative response to the severely constrained space available to this artist. There simply is not room to show the celestial actions of God on high at the same time that the angel, on earth, is announcing the news to Mary, but the presence of the dove is able to convey that celestial dimension, hovering right beside Mary.
Just as with the words "Ave Maria," the dove is not mentioned in the Biblical text for the annunciation scene. The Gospel of John, however, does tell us that at the time of Jesus's baptism, a dove appeared: "Then John [the Baptist] gave this testimony: I saw the Spirit come down from heaven as a dove and remain on him."
This makes for a perfect creative connection between the baptism scene and the annunciation. In the Gospel of Luke, the angel of the annunciation tells Mary that she will be visited by the Spirit: "The angel answered: The Holy Spirit will come upon you, and the power of the Most High will overshadow you."
As you can see in this image, the artist has imagined the Spirit coming upon Mary in the form of a dove, just as in John's version of the scene of Jesus's baptism: