Why do we have to learn prayers? Why can't we say our spontaneous prayers?

The important things is not to just express words but to speak to God from your heart. If you prefer to express yourself in your own words,you are free to do so.However, you will discover that knowing prayers by heart helps you in moments when you don't have the inclination or ability to say your own prayer.

What is the way of prayer?
Prayer is primarily addressed to the Father. Prayer is directed to God our Father but reaches only when we pray - at least implicitly- in the name of Jesus. Our prayer is efficacious when it is united in faith with the prayer of Jesus. Jesus said, "If you ask anything of me in my name, I will do it" (Jn 14: 14). Jesus is the one and only mediator between God and men. His humanity is in effect the only way by which the Holy Spirit teaches us to pray to our Father. Therefore liturgical prayers conclude with the formula: "Through our Lord Jesus Christ."

Prayer can also be directed toward Jesus, particularly by the invocation of his Holy Name: "Lord Jesus Christ,Son of God,have mercy on us sinners." By this prayer the heart opens up human wretchedness to the Saviour's mercy. Jesus always prays for us.All our petitions were gathered up, once for all,in his cry on the Cross and, in his Resurrection, heard by the Father. This is why he never ceases to intercede for us with the Father. If our prayer is resolutely united with that of Jesus, in trust and boldness as children, we obtain all that we ask in his name, even more than any particular thing: the Holy Spirit himself, who contains all gifts.

"No one can say 'Jesus is Lord' except by the Holy Spirit" (1Cor 12:3). The Church invites us to invoke the Holy Spirit as the interior Teacher of Christian prayer. Since he teaches us to pray by recalling Christ, how could we not pray to the Spirit too? That is why the Church invites us to call the Holy Spirit every day, especially at the beginning and at the end of every action. The simplest and most direct prayer is the traditional,"Come Holy Spirit!" It is in the communion of the Holy Spirit that Christian prayer is prayer to the Church.

Mary,Jesus'mother and ours "shows the way", and is herself "the sign" of the way of prayer. Because of Mary's singular cooperation with the action of the Holy Spirit. the Church loves to entrust her supplications to the Virgin Mary and pray in communion with her. The Church also joins her prayers with those of all the saints who have been pleasing to the Lord because they willed his will alone. [See CCC 2663- 2682]

Father Dominic. in his sermons, tells us to always have the name of Jesus on our lips. What is the reason?

The name Jesus in Hebrew means: "God saves." The name of Jesus fully manifests the supreme power of the "name which is above every name" (Cf. Jn 12:28)."There is no salvation through anyone else, nor there is other name under heaven given to the human race by which we are to be saved"(Acts 4:12). The evil Spirits fear his name;In his name his disciples perform miracles, for the Father grants all they ask in this name(Cf. Acts 16:16-18;19:13-16; Mk 16:17; Jn 16:16). The name of Jesus is at the heart of Christian Prayer. All liturgical prayers conclude with the words "through our Lord Jesus Christ". The Hail Mary reaches its high point in the words "blessed is the fruit of thy womb Jesus." The Eastern prayer of the heart,the Jesus Prayer, says: "Lord Jesus Christ, Son of God, have mercy on me,a sinner." Many Christians such as St. Joan of Arc, have died with the one word "Jesus" on their lips.

The invocation of the Holy name of Jesus is the simplest way of praying.When the  the Holy Name is repeated often by a humble and attentive heart,the prayer is not lost by heaping up empty phrases, but holds fast to the word and brings forth fruit with patience. This prayer is possible at all times because it is the only occupation: that of loving God, which animates and transfigures every action in Christ Jesus. So, its one of the best things you can do to humbly repeat the name of Jesus at all times.[See CCC 430-435,2668]   

What is the Origin of the "Hail Mary"?

The first part of the "Hail Mary" is taken entirely from the Gospel. Read  Luke 1:28 and Luke 1:42. The second part is a text formulated by the Church during its history.

Hail Mary [or Rejoice,Mary]:the greeting of the angel Gabriel opens this prayer. It is God himself who, through his angel as an intermediary, greets Mary. Our prayer dares to take up this greeting to Mary with the regard God had  for the        lowliness of his humble servant and to exult in the joy he finds in her.

Full of grace,the Lord is with thee: These two phrases of the angel's greeting shed light on one another. Mary is full of grace because the Lord is with her.
The grace with which she is filled is the presence of him who is the source of all grace. "Rejoice... O Daughter of Jerusalem... the Lord your God is in your midst."Mary in whom the Lord himself has just made his dwelling, is the daughter of Zion in person, the ark of the covenant.The place where the glory of the Lord dwells. She is "the dwelling of God...with men." Full of grace, Mary is wholly given over to him who has come to dwell in her and whom she is about to give to the world.

Blessed art thou among women and blessed is the fruit of thy womb, Jesus: After the angel's greeting, we make Elizabeth's greeting our own. "Filled with the Holy Spirit," Elizabeth is the long succession of generations who have called Mary "blessed." "Blessed is she who believed..." Mary is "blessed among women" because she believed in the fulfillment of the Lord's word. Abraham, because of his faith, became a blessing for all the nations of the earth. Mary, because of her faith became the mother of believers, through whom all nations of the earth receive him who is God 's own blessing: Jesus the "fruit of thy womb."

Holy Mary, mother of God: With Elizabeth we marvel, "And why is this granted me, that the mother of my Lord should come to me?" Because she gives us Jesus, her Son, Mary is Mother of God and our mother, we can entrust all our cares and petitions to her: she prays for us she prayed for herself: "Let it be  to me according to your word." By entrusting ourselves to her prayer, we abandon ourselves to the will of God together with her: "Thy will be done."

Pray for the sinners, now and at the hour of our death: By asking Mary to pray for us, we acknowledge ourselves to be poor sinners and we address ourselves to the "Mother of Mercy," the holy one. We give ourselves over to her now, in the today of our lives. And our trust broadens further, already at the present moment, to surrender "the hour of our death" wholly to her care. May she be there as she was at her son's death on the cross.May she welcome at the hour of our passing to lead us to her son, Jesus, in paradise. [ See CCC 2676- 2677 ]