I suppose if I yell loud enough it might have some affect on reality (shattered glass, bleeding ears, all that jazz) and in the same way in relation to what I say the world is going to change to some extent (say if I convince someone to do one thing rather than another). Maybe I'm misreading what you're saying but if not then I think you might be missing the point. Sure in the sense that language is a part of reality and thus has a bearing on reality (just like any action someone performs will have an effect) it influences reality. But I was making the point that language influences the way we perceive reality.
I'm not sure if I can get at the difference between our points but I feel there is a fundamental difference that, when realized, will actually make what appears to be a problem a non-issue.
To the extent that language is simply vibration it can only have effect in relation to its magnitude. For example, a loud blast may cause reality to change by causing me to go deaf. This is what I thought you were saying and which I agree with but isn't the point of what I said earlier.
To the extent that language is a SOUND that signifies something it also effects reality. For instance, a siren blaring automatically makes me think that I need to get out of the way. Contrary to the loud blast, the siren actually references something in the real world. (I know that a siren isn't language but just humor me
In this sense, language as vibration can certainly influence reality by having natural effects (like the loud blast) or tied up in the usage of language it can influence reality by having effects on people which lead them to do things they would not otherwise do.
But in the sense of changing reality as far as the meaning of a word changing the way the world actually is, I think it's false. Reality is the way it is regardless of the words we choose to use. In the car crash example, the glass is NOT broken. But the words used can influence people and change their perception of the accident so that they will believe that the glass IS broken. This isn't changing reality, it's changing perception.
Hopefully that clears up what I meant. I hope it makes sense.