These are some possible ways of coming closer to C1 / C2 Esperanto for those who already are advanced EO learners [not counting myself!]
. And again, tools are tools. Everyone could simply cherry-pick what they like.
- As for the reoccurring words that still wouldn't stick too well, they and their example sentences could be copied and pasted to a notebook file or cited in a (physical) notebook.
- After doing so, a multitude of Spaced Repetition Approaches can be applied. What I personally like to do with "any" language is to add a dot or a vertical bar after every repetition.
- As for the active language skills (speaking and writing), I sometimes really like the idea of Workaround Words. I.e. expressing something by a term that isn't the Most Straight-Forward and Most Eloquent Way of Saying Something, but it still does serve its purpose. For example, in some situations one could say "baking thing" instead of "oven" in English because of simply not knowing it yet. Not denying either that it could be counterproductive in some other situations.
- It could be useful to make a difference between having a General C1 / C2 Understanding of Esperanto and knowing all those Specific Jargon Terms out there. To me, "jargon" isn't restricted to rocket science or anything like that. Sometimes I would even call any language's Vocabulary Subset related to cooking, baking, painting, etc., a jargon. There are many people who aren't too familiar with some of those topics even in their native language. And they don't know too many of their specific terms, even if they are Very Very Every-Day Usage to others. Now would those who don't know these expressions be non-fluent or below C2?
- Some Esperanto words could be difficult to remember for some of the EO learners who are natives of any Germanic or Romance language. If those particular words don't seem too familiar to them because they neither resemble anything Germanic or Romance, nor any of the usual Genuine Esperanto Words, the reason may be their Slavonic origin. L. L. Zamenhof (the inventor of Esperanto) did include a certain amount of them as well. He was very, very familiar with them because of his native language / etc. . It also could help to read just a little bit about the origin of those words or even about Slavonic languages in general. However, I wouldn't consider this to be a Major Puzzle Piece, speaking of the EO learning process.
- As for the Very Rare and Entirely Low Frequency Words, I personally wouldn't worry about them at all. They exist even in one's mother's tongue.
- There is a large number of compound words that basically become clear by knowing the meanings of their base stem and the meaning of the additional affix/es. However, reading some example sentences (especially if they are Real World Usage Based) does have some major merits.
- For those of us who have got an affinity to visual arts: Connecting this hobby to EO learning can result in a Synergy Effect (by the way, this is one of my Most Favorite Expressions
- Read about some subjects in both of EO and another language (native or not) can be another means of coming closer to C1 / C2.
- Finally, there also is the possibility of thinking once again what C1 or C2 exactly means to oneself, then checking whether this stage really is still "that far away" or not. Some just might discover being closer to it than they used to think.