The internal narrator is only one form of thought.
One meditation technique is to quickly label each passing thought (it’s called “noting” I believe). At some point you can begin to label the narrator process itself and see it separate from your other thinking processes (“voice” I call it, though it becomes wordless at that point).
[Edit: nevermind the Focusing link actually mentions the labeling. Though I recall Focusing was more about depth of analysis, not fast, high frequency labeling]