I get the same thing. I work in a job where I have to make radio calls over a Motorola handheld and I get a block everytime when saying my unit number. Those are the only times where my block gets obnoxious and I am also wondering about tips. Some things that have worked for me in the past have been: 1. Taking a deep breath before speaking 2. Starting my sentence with another word which helps me flow into the block word. 3. Word substitution. This one cannot always be used if the block word is vital (such as my unit number).