"When ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking" (Matthew 6:7).
The quality of our communion with God is more important than the quantity. Our prayers are to be "effectual," and thus directed by the Word of God and the Spirit of God (James 5:16). Mere prayer for prayer's sake is an empty exercise that may do more harm than good, tempting us to believe that our relating to God is real when it is actually little more than ritual.
A few words of genuine prayer are more consequential than millions uttered as rote and ritual, or as a means of convincing ourselves that we are fulfilling an obligation to God. Such motivation results in idle chatter that is as meaningless to God as it would be to any loved one who perceives our words to lack heart and substance. We are not heard for our "much speaking," but rather for our coming to God through the way He has made, the Lord Jesus Christ, and by the Holy Spirit's working in us to produce authentic relationship with our Heavenly Father.
At the end of history, we may discover that very few prayed very much, and of those who prayed very much, very few prayed very well. One of the foundational Biblical truths of prayer is that "we know not what we should pray for as we ought" (Romans 8:26). Humble confession of our weakness in the matter is therefore a primary understanding that leads and enables genuine communion with God. Trusting in the Holy Spirit's guidance is also vital, and then a great sense of awe and seriousness must govern our awareness that God calls us to living relationship with Him. Fewer and better words will likely be the fruit of such understanding, and a more consistent practice of approaching the throne of God in a manner more satisfying to Him, and to ourselves.
"The effectual, fervent prayers of a righteous man availeth much."
"And this is the confidence that we have in Him, that, if we ask any thing according to His will, He heareth us."
(I John 5:14)