The fear of not being able to get the word out, is the fear of stuttering. Stuttering isn't only repetitions like b-b-b-ball. When we get hard blocks, we are holding back from making sound because we are afraid of how it may come out and we want to make sure we're in control before we say it. That's a reason why we often block and wait until we feel comfortable enough/safe enough for how the word will come out. A lot of us have this problem. We are ok with stuttering up to a certain level of stuttering, but sometimes a word or sound is too difficult for us to stutter "pretty" on we won't physically let ourselves just blurt it out, no matter how much we tell ourselves we want to. This isn't something you can change in a week. Techniques aren't going to help you for the reasons im sure you've already realized. They're not going to work when you need them most. You could probably train yourself to use your techniques all the time to develop a new way of speaking, but that sounds pretty awful to me. The way i've found to approach this is to take really small baby steps a couple times a day (seriously, don't try to work on this all the time). Something like the next time you feel a feared word coming up, just try to make any noise in that feared sound you're blocking on. Don't worry about the rest of the word, just try to get sound in. If that's too hard, try to just stay with it for a second longer than you normally would before you retry. You won't be able to do this in difficult situations, but start in safe situation where you still sometimes occasionally get blocks and practice. Also, what's more awkward, starring at someone frozen in place mid sentence with you feeling the weight of every second and them having no clue what's going on, or stopping to say "wow, this word doesn't want to come out lol". I think you might be surprised. Just dont feel bad about yourself if you do it.