Here goes, if I miss anything I apologize
1. Do you remain a cadet in the Air Force or do you still commission to pursue your master's degree?
No, you are not a cadet, you are a commissioned officer. You will receive O1 pay, medical bennies, and BAH like any other officer. Your job is to attend grad school.
2. Are you on the reserves while doing this?
Not in the sense that you are thinking.
You may be required to spend the summers on casual status at wherever they choose if your grad school is not yr round, but most go yr round, so you are most likely not going to go reserves.
AFROTC cadets are all commissioned into AD AF, not AF Reserves, which is traditionally a guard unit.
3. Do you still advance in rank?
Yes, for the AF you will make O2 at 2 yrs just like every other officer.
4. Are there any other ways I can pursue my degree?
Yes, it is called Tuition Assistance Program (TAP).
Every base have satellite colleges through their education dept. ERAU, Webster, UMDCP, Troy, etc are just a few that offer not only undergrad degrees, but grad degrees too through a night/weekend school process.
AF will pay 75% of the tuition, HOWEVER, you will owe 3 yrs everytime you take TA. It runs concurrent with your commitment.
For example, if it takes you 2 yrs to complete, you would owe 5 yrs total because the last time you took the TA was at your 2 yr marker. You walk in with owing 4 yrs, so in essence you only owe 1 more yr.
This is true for ED also.
5. An officer told me once that since it's a critical language degree the military could assign me when I'm on active duty to pursue the a graduate in that language but another officer said that wasn't true. Can anyone confirm?
From what I have always understood if you ask to go into this program, it is for specific needs of the AF, so I would say that if you are asking them to pay, they will want a voice in your decision.
Look at HSSP, AF has a voice in your major when handing out that scholarship.
You may want to major in Russian, and they may say "No, if you want it you will major in Chinese or Farfsi".
Their dime, their needs.
The last thing to state, not necessarily for you yourself, but other posters and lurkers. If you also want to go rated, this can be an issue for you because now the AF may say we need you more in that field over flying. You risk closing a career field door.
Most ED's will have what is called a follow on assignment. In other words you will know what AFSC you will have after grad school prior to your commissioning.
One other thing, understand it is highly competitive, and I would ask your CC now about the chances of them supporting you for this as your number 1 pick.
Grad school is actually common for many posters here on this site, but most of the posters that are doing ED right now come from the AFA. Hornetguy (RAND) and Eagle (WP) are both in the grad program. Christcorps DS is a Firstie and applying now. I believe one of Fencers twins is also trying this route. You may want to PM them about how the process works, I don't think any of them are in the language program, but at least they can assist you in how it works to get into the ED.
Good luck