He was praying in a certain place, and when he ceased, one of his disciples said to him, "Lord, teach us to pray, as John taught his disciples." And he said to them, "When you pray, say:
"Father, hallowed be thy name. Thy kingdom come. Give us each day our daily bread; and forgive us our sins, for we ourselves forgive every one who is indebted to us; and lead us not into temptation." Luke 11:1–4 (RSV)
Likewise the Spirit helps us in our weakness; for we do not know how to pray as we ought, but the Spirit himself intercedes for us with sighs too deep for words. And he who searches the hearts of men knows what is the mind of the Spirit, because the Spirit intercedes for the saints according to the will of God. Romans 8:26–27 (RSV)
Can you remember learning to pray the Lord's Prayer? If you were born in a Christian home, a worshiping family, the Our Father is woven your being. It makes almost as much sense to ask when you learned to breathe. One hardly needs to think about the Lord's Prayer.
I expect reading the Lord's Prayer as St. Luke recorded it in his Gospel tripped you up a bit. It is a challenge to read it as parts of it are missing. We are so locked into St. Matthew's version than any other seems wrong.
St. Luke does record the disciples asking Jesus to 'teach them to pray'. We have begun to confess those words as we prepare to pray the Our Father. We need to learn the prayer. This does not mean that we are not able to recite the Lord's Prayer. A small child can learn to do that.
No, we need to be taught to regard the words of the Lord's Prayer as life-giving, life-sustaining. We learn the depth of the Father's mercy and grace as our lips form the words. We want to be taught the Lord's Prayer by the Lord, so each word becomes more precious to us than our breath.
St. Paul reminds us how vital our prayers are to the Father. Even as we are learning the Lord's Prayer as the bedrock of our life of prayer, St. Paul teaches that the Father will not let our prayers go unspoken. Thus the Holy Spirit journeys through our heart and soul, searching out every syllable of prayer that we cannot put into words.
The Spirit prays what we cannot pray with the language of heaven. There is no prayer we can pray or not even understand. There is a prayer within us which the Spirit lifts before God.
A lifetime of one hundred years is hardly a beginning in prayer. The Lord's Prayer is simple to pray and takes a lifetime to learn the love contained within it. Thanks be to God through His Holy Spirit that we learn to pray, even when we have no words.