Hideyoshi,
I'll be honest with you and tell you that your voice sounds unnatural. It seems you're forcing it too much and speaking from your nose. Mickey mousey, nasal...my point here is not to be rude, on the contrary, I want to help you...so it's constructive criticism. Please don't take it in the wrong way. Your voice also doesn't match your face. You need to tone it down, I think and just speak from the upper half of your throat, if that helps in understanding it a little better. 🙂
I really hope I didn't offend you. I want to help, remember this.