Solo traveler in Paris needs advice

If going straight to the airport, there is one early morning train that is direct [from Dijon] at 7:06. You could drop your luggage at your airport hotel, then go into Paris for the rest of the day.

Leaving Dijon later, you have to change to the RER at Gare de Lyon to get to CDG. Easiest is to take the RER A to Chatelet-Les Halles and do a simple cross platform change to the RER B that goes to the airport. Ticket is now 10.30 EUR.

If you decide to get a hotel near Gare de Lyon, you can also take Le Bus Direct from Gare de Lyon to the airport with your luggage in the bus hold. 17 EUR with an advance ticket or 18 EUR bought from the driver. Leave by 6:45 for a 10:30 flight. There are also buses at 5:45 and 6:15.

You should be fine as English is the universal 2nd language. Bus driver might not know any English, but it will be an obvious transaction. He/she will want to know what terminal you are going to. Train station personnel will have English speaking agents, as well as hotels.

Since your flight leaves in the morning I would stay at a hotel at the airport. There are several that are actually in the terminal or have direct access. This way you won't have the worry of getting to the airport by train in the AM.

I have stayed at the airport before when my flight left at the same time as yours and I was able to sleep in and get to my flight with a lot less stress.

If I were you and I was nervous about getting to the airport for my flight, but arriving into Paris the day before by train. I would stay at a hotel near my arrival station (from Dijon), and have the hotel order a taxi for me for the following morning. That way I could enjoy Paris on my own and not worry about any additional trains. And the taxi would relieve any stress of getting to the airport solo. Do what you find the least stressful, not necessarily the least expensive. You can experiment the next trip if you want to do so, but at a time when you don't have to worry about catching a flight, etc.

Paris Gare de Lyon is the arrival station for TGVs from Dijon and does have direct service to CDG by Le Bus Direct, so that would be my preference over a taxi. I've had good luck with these buses, but of course, if one didn't leave on time, then taxis would also be available near the station as plan B (50 euros).

Taking a train and a plane is a pretty easy task to do. Doubtful that you'll need to do any real communication . Just pick up your ticket, validate it at one of the yellow machines (if it says "Composter", you need to validate it. ) hop on the right train (don't arrive at the train station too early because trains leave normally when they say they leave and don't always arrive much before then).
Also, consider learning some simple conversational French. Numbers 1-10 are useful. Counting is different on the fingers so holding up what you think is #1 might get you #2. English isn't as widespread as everyone thinks. Think of people in the US who took a language in high school---generally they aren't fluent but know a few words to get by. Imagine someone coming up to your city speaking French. It's the same thing. Have a great trip!

There are a couple of TER trains from Dijon to Paris that need to have tickets validated in a stamping machine. But they take nearly 3 1/2 hours and stop at Bercy station, which is short of Gare de Lyon and kind of leaves you out in left field. The more frequent TGV's take only a little more than 1 1/2 hours and leave you at Gare de Lyon with lots of transport options and nearby hotels. They will have reserved seats, so nothing to validate. There is also that morning TGV direct to CDG airport.

The TGV's are more expensive, but you can buy a nonrefundable ticket now if you know your schedule is set.
Print-at-home tickets can be bought now assuming this journey is in the near future. Let you credit card co know that you are making a foreign purchase. Tickets at:
https://en.voyages-sncf.com/en/tgv
If you have credit card issues, try www.trainline.eu.
Same prices, print-at-home tickets, and easier credit card approval.

I recently made the trip to CDG from Gare du Nord. Signage is good so it is an easy trip to make. The tracks are adjacent to the escalator and are indicated by a single letter mounted on the brick. Just find your letter and go downstairs to your track.

Make sure you know which of the two stops the train makes at CDG is most convenient to your airline. RER stop #1 is for CDG terminal 3. RER stop #2 is for CDG terminal 2. This page lists the terminal each airline operates from.
http://easycdg.com/airport-guide/which-terminal-paris-cdg-airport-charlesdegaulle/

Trains run every 6 to 15 minutes. It takes 35 minutes to get to CDG. Tickets are 10 euros and they can be bought from the machine with coins or credit card.
http://easycdg.com/transport/charles-de-gaulle-airport-cdg-to-paris-by-rer-train/

Here is a map of the RER line from Paris to CDG. Note CDG is on the left side of the map.
http://www.about-paris.com/rer-b-paris-to-cdg-plan.htm

This map shows the stops and provides a little more terminal information
http://www.experienceloire.com/cdg-plan.htm

Agree with Barbara about staying at an airport hotel -- we have stayed at the Ibis at CDG twice and walked to the intra-terminal shuttle train for a morning flight.

Make your life simple and follow the advice of taking Le Bus.

Your flight leaves CDG at 10:30. You need to be at the airport no later than about 8:00. If you stay in Paris, that means getting to Gare du Nord about 7:00 to buy a ticket, find your way, etc. And then the travel time from your hotel to Gare du Nord.

However, when you arrive at Gare de Lyon, all you have to do is find Le Bus. (Not difficult) It will take you to CDG. Stay at a hotel near CDG and your commute time the next morning will be minutes.

Agree with advice to stay at CDG. Otherwise you'll be worried about it the whole time and it'll spoil your trip. Have a great time!!

If you are starting for Gare du Nord from a local Metro station, one ticket covers both subway and RER to CdG. Keep the ticket all the way as you will need it to exit the RER at the airport. The ticket can be bought in advance to avoid day-of-departure stress.
At Gare du Nord, the RER trains can be found at the right side of the big station. Lots of signs and only one trick: There are two banks of escalators going down to the train platform and you want the set on the left. For reassurance, here are some photos: www.parisbytrain.com