As a former Buddhist, I can tell you that the Jesus Prayer as done by Orthodox monks is almost exactly like Buddhist monks pray. They say the prayer so fast it becomes like a humming noise.
Should Christians pray as pagans do? Its just a question. What about repetitious prayers? This question is just food for thought. Be careful lest you too become an incoherent babbler.
This is just my opinion. But its also one of the reasons I didn’t go to the Orthodox church. As a former Buddhist I did find it disturbing.

If I had a nickel for every person who thought something wonderful would happen if they repeated something ad nauseum.
Do you really think that God is impressed with your ability to say something fast 1,000 times!
Is that how we get into Heaven? Is that what Jesus said?
Please, use your head and your intellect because God gave it to you, in order to know him and follow him. Where do we see Jesus doing repetitious prayers fast?
Buddhism predates Christianity, and I am sure that when he said don’t pray as the heathens do he was referring to those pagans who thought that by their numerous repeated prayers they would get into Heaven.
But is that THE WAY Jesus preached?
Please, think before you copy others behaviors. Repeating things over and over again is really easy. But the way that Jesus led us to is not easy. Be careful with how much time you waste. Read the bible instead and get to know Jesus.
If you feel that you must repeat a sentence over and over again then just make sure you read the gospels for 10 or 15 minutes first.

Try and understand what Jesus wants you to do.