Wow, I thought I was the only other person on Earth who felt this way! And I figured it was because of my own limitations rather than necessarily because of any explicit Biblical basis.

I cannot "pray silently" at all. My thoughts get all jumbled, some are addressed to God and others to myself or someone else other than God, and I find that I must speak the words of my prayers just to keep my mind on track. I've always assumed that my scattered thoughts and the need to use something "external" like spoken or written words in order to focus, was just another facet of my autism (since most people apparently don't have the same difficulty) and it kinda sorta "keeps time" with all the sensory issues. Praying - even thinking - "out loud" is the only way I can really do either one effectively. So that is reason enough for me to pray "out loud," which I tend to do in writing or whispered into my hands while others are "praying silently." Now you have added some Scriptural reasons to do it! Thanks, Tracylight!

-R