When someone learns a language at the DLI basic course, do they learn just enough or will they be almost completely fluent in that language?

SPC Russ Knott 2/2 is MOS immaterial. To graduate DLI, you need a 2/2 in whatever language you are assigned. If you know what language you will be assigned, study that. If not study how English works, so you have a better grasp of how language as a whole works. Understand participles, gerunds, cases, declension, conjugation, etc...

SPC Russ Knott you won't be a linguist, that's a different MOS. You will be required to reach and maintain a 2/2 your whole career.

To study prior to the school, just study the language you received prior to school. There's lots of free language training. DLI will start in English and quickly move to being conducted 100% in the language you're learning.

As far as fluency, that's a scale. You'll be about as fluent as a hillbilly or middle school kid with a 2/2. You'll have later opportunities to attend DLI again for advanced language training and you'll receive funds for language training and immersive language training exercises throughout your career

SPC Russ Knott - a 2/2/1+ isn’t all that competent. You’ll be able to get through the airport, watch the local news broadcast and get a good portion of it, talk with some locals, etc. However, you won’t be able to get into a heated argument, you won’t understand native humor, and you probably won’t be able to get into a cross talk rapid fire conversation with several people. And native speakers will always be able to tell that you are definitely not fluent.

Anyone that’s been there will tell you that DLI is like drinking from a firehose. It never really gets easier. As for studying before hand, start on YouTube and learn your languages alphabet, Written/spoken/pronunciation. And then go from there. Youtube is actually pretty great.

Good luck, DLI is pleasantly awful.
http://moodyfss.com/wp-content/uploads/2015/10/DLPT_Score_Definition.pdf

SGT (Join to see) LOL! I love your description and I have a way better understanding now. My son is the one that will be attending the school to learn Russian for 35M. I’ve been helping him learn Russian ahead of him attending the school just so he can have a little more of a fighting chance. We’ve been using the language learning app Babbel and I’ve been making electronic flashcards off of that for him. I’ve also been quizzing him on vocabulary, sentence structure, and verb conjugation.

He doesn’t leave for basic until June, so hopefully by then he’ll have an even better vocabulary and understanding.

Thanks for your description of what 2/2 means. It’ll help with our current learning!

Actually, they'll have the equivalent of a Middle School vocabulary and an Elementary School understanding of history, customs and culture. After graduating (with Merit), I was able to conduct a simple conversation, arrange transportation, order some meals, and partially understand native conversations. Most native speakers, spoke to fast for me to keep up with unless they were talking directly to me.
On the bright side, when I found myself out after curfew trying to find my bivouac in blackout conditions on a ROK Marine Base and heard the distinctive sound of an M-14 bolt sliding home, I did remember enough to prevent being shot and get directions for "the stupid American".