What is really behind Davening?

(2) Shimon the Righteous was one of the last of the men of the great assembly. He used to say: the world stands upon three things: the Torah, Davening, and the practice of acts of piety.

The Gemara answers: As it was taught in a baraita with regard to the verse: “To love the Lord your God and to serve Him with all your heart” (Deuteronomy 11:13). Which is the service of God that is performed in the heart? You must say that this is referring to prayer.

(1) It is a positive Torah commandment to pray every day, as [Exodus 23:25] states: "You shall serve God, your Lord." Tradition teaches us that this service is prayer, as [Deuteronomy 11:13] states: "And serve Him with all your heart" and our Sages said: Which is the service of the heart? This is prayer.
The number of prayers is not prescribed in the Torah, nor does it prescribe a specific formula for prayer. Also, according to Torah law, there are no fixed times for prayers.

Rather, this commandment obligates each person to offer supplication and prayer every day and utter praises of the Holy One, blessed be He; then petition for all his needs with requests and supplications; and finally, give praise and thanks to God for the goodness that He has bestowed upon him; each one according to his own ability.

(4) When Israel was exiled in the time of the wicked Nebuchadnezzar, they became interspersed in Persia and Greece and other nations. Children were born to them in these foreign countries and those children's language was confused.
The speech of each and every one was a concoction of many tongues. No one was able to express himself coherently in any one language, but rather in a mixture [of languages], as [Nehemiah 13:24] states: "And their children spoke half in Ashdodit and did not know how to speak the Jewish language. Rather, [they would speak] according to the language of various other peoples."
Consequently, when someone would pray, he would be limited in his ability to request his needs or to praise the Holy One, blessed be He, in Hebrew, unless other languages were mixed in with it. When Ezra and his court saw this, they established eighteen blessings in sequence.
The first three [blessings] are praises of God and the last three are thanksgiving. The intermediate [blessings] contain requests for all those things that serve as general categories for the desires of each and every person and the needs of the whole community.
Thus, the prayers could be set in the mouths of everyone. They could learn them quickly and the prayers of those unable to express themselves would be as complete as the prayers of the most eloquent. It was because of this matter that they established all the blessings and prayers so that they would be ordered in the mouths of all Israel, so that each blessing would be set in the mouth of each person unable to express himself.

(3) And the wise one will understand on his own that it wasn’t for no reason that the one-hundred-and-twenty elders (and among them a few prophets) set the requirement for such a brief supplication and a short prayer such as this. Rather, that they [emphatic] discerned with their Holy Spirit and with the discernment of their supernal prophecy, and all the paths of the designs of the Creation and the parts of the Vehicle shone brightly for them, and because of this they set the foundation of and fixed the form of the blessings and the prayer service using these specific words.

(18) 18. The Kuzari says: Why is this? If every one read his prayers for himself, would not his soul be purer and his mind less abstracted?

(19) 19. The Rabbi: Common prayer has many advantages. In the first instance a community will never pray for a thing which is hurtful for the individual, whilst the latter sometimes prays for something [to the disadvantage of other individuals, or some of them may pray for something] that is to his disadvantage. One of the conditions of prayer, craving to be heard, is that its object be profitable to the world, but not hurtful in any way... A person who prays but for himself is like him who retires alone into his house, refusing to assist his fellow-citizens in the repair of their walls. His expenditure is as great as his risk. He, however, who joins the majority spends little, yet remains in safety, because one replaces the defects of the other.

He shouldn't pray the short prayer in the singular , rather in the plural, because through this his prayer is heard.