I think this is partially correct. Inner monologue is not an illusion, and choosing a wrong linguistic construct for your audience (sometimes from another language) through temporarily forgetting to context switch does happen. However, thinking something without ever having done so in words does seem to strongly correlate with your assertion.

Tangentially, I realised in high school that I was doing almost all math operations as word transformations. I reasoned this was why even familiar procedures for which I confidently & consistently got correct results were taking substantially longer than everybody else. I was translating everything twice.