The following story about the pronunciation of a Mantra between a Guru and his disciple may help us to decide how a Mantra should be pronounced.

A devoted meditator, after years of concentrating on a particular Mantra, had attained enough insight to begin teaching. The students' humility was far from perfect, but the teachers at the monastery were not worried. A few years of successful teaching left the meditator with no thoughts about learning from anyone; but upon hearing about a famous hermit living nearby, the opportunity was too exciting to be passed up.

The meditator gave him the correct pronunciation, and the old hermit was very grateful, asking to be left alone so he could get started with that Mantra right away. On the way back across the lake the meditator, now confirmed as an accomplished teacher, was pondering over the sad fate of the hermit. He thought - "It's so fortunate that I came along. At least he will have a little time to practice correctly before he dies." Just then, the meditator noticed that the boatman was looking quite shocked, and turned to see the hermit standing respectfully on the water, next to the boat.

"Excuse me, please. I hate to bother you, but I've forgotten the correct pronunciation again. Would you please repeat it for me?"
"You obviously don't need it," stammered the meditator; but the old man persisted in his polite request until the meditator reluctantly told him again the way he thought the Mantra should be pronounced.

The old hermit started saying the Mantra very carefully, slowly, over and over, as he walked across the surface of the water back to the island as he came from the island.