There is a story that the Russian czar once found out about a certain artist that did beautiful work and therefore invited the artist to his palace. The artist arrived and was so much in awe of being in front of the czar that he could not speak. The czar asked him questions, but the man became a mute.

This is the way we should be when we come to Shemone Esray. We are standing before the King of Kings, Holiest of the Holy, the Greatest One in the Universe, The Holy One Blessed Be He. We should be in so much awe that we cannot speak. That is why we begin Shemone Esray with Hashem Open My Lips (Hashem Sefasi Tiftach). We should be in so much awe that we cannot speak that we need to daven for the ability to speak.