I think that fear has a deeper underlying emotion. The underlying emotion of feeling the need for filtered speech execution (in a way, we likely have a software in our mind that we have programmed to filter and edit the speech initiation based on how we perceive and anticipate our speech performance and negative reactions or judgements (pre-programming of this inhibitory mechanism). Conclusion: So if we try to execute speech movements anyway whenever our subconscious mind is abnormally filtering our speech execution (to protect us from any perceived 'imagined' reason that we've pre-programmed in our software, in our hippocampus), we continue stuttering. I argue that it's not really a basal ganglia problem then, rather it's more a hippocampus problem where the software (that functions as a defensive mechanism) is subconsciously running in the background, sabotaging each speech execution attempt under the guise/pretense of a filter emotion. It is exactly because we rely on the faulty hippocampus programming, that it disrupts basal ganglia processing. This is just my own take on it