Hi James,
There are a number of medical and education explanations of how and why this occurs. The primary problem when this occurs is that the brain is working very hard to find a neuro-pathway from the command center to the tongue. When stress or nerves become too much then the pathway becomes overloaded with too much stimulus and the right word(s) are hard to find. By taking a breath, stepping back and pausing for a second or two the brain can find the word, the pathway is cleared and the word can be transferred to the tongue. The key… >>>