I did understand what you said. It makes me realize that my original comment included several requests:

(1) Provide a search that automatically looks for fuzzy matches. The current search engine (Sphinx) doesn't do this.

(2) Provide functionality that allows you to perform a search through the corpus for the content that you're about to submit. If part 1 is implemented, then this search can find similar as well as identical sentences.

Currently, in order to search for content that you're about to submit, you basically need to keep a separate open Tatoeba window, then copy your content (wrapped in double quotes if you want to find an exact match) into the Tatoeba search bar. This takes up extra screen space and of course also requires extra manual effort. As a result, I suspect that few people look for duplicate or related sentences on every submission. (Realistically speaking, it probably only makes sense to do these searches on short sentences with common vocabulary.) There is a script that is run periodically on the corpus to merge exact duplicates, so adding them is not as problematic as it might be. However, it's still a pretty complicated task to merge comments and histories as well as content, so avoiding the insertion of duplicates in the first place is preferable, especially if you're an advanced contributor, which gives you the ability to link to existing sentences.

It sounds like you're talking about an ability to manually create a new kind of metadata link that would aid fuzzy searches by including searches for synonyms, rather than relying on some existing synonym dictionary to do the fuzzy search. Is that right?