What’s the deal with output?

Somehow I reached the point where I can watch JP Anime without subtitles (albeit with a few lookups per Episode), however my output is still like that of a kindergartener's. I can say very basic things "well", so long as I chain together slightly altered sentences that I memorized or stick to a basic script, however the moment that I deviate from it, I immediately fall into that weird unnatural zone where no one can understand what I'm saying except for me.

How do I stop sucking so much? I understand that I could theoretically gain some EXP by immersion diving, however there are some things that I want to say that cover topics so obscure that if I don't say them: no one will.

by AnonymousMite