Welcome!
1. Of course, it is difficult to truly pinpoint the causes of any particular score after a lifetime of experiences, but generally, your scores suggest that you are high average in most areas, including abstract/fluid reasoning, both verbally and nonverbally, and processing speed. Your working memory appears within normal limits. Verbal knowledge (crystallized intelligence) often represents verbal long-term memory. It does not require extensive formal education, as the knowledge is such that you could have acquired it from reading extensively, or making yourself available to a range of experiences and knowledge, such as from watching science or history programming on television, visiting museums, or being generally inquisitive.
2. The best measure of your overall cognition remains the GAI or FSIQ, as the FSIQ includes measures of cognitive efficiency as well as reasoning, and the GAI is a broader measure of reasoning ability than any index alone. However, the VCI is likely to be a better representation of your language-related abilities, especially for contextualized (personally meaningful) language tasks.
3. Classification as GT or no has limited utility outside of the K-12 educational system. More importantly, you should recognize that you have some marked strengths in the language area, and are likely to feel most fulfilled intellectually when you are able to feed your personal quest for knowledge.
I hope you find what you need.
