If you are fortunate enough to have a copy of Camtasia from TechSmith, you can use that to make your videos accessible to all with captioning. The software is about $300 for a copy, but, it's worth it. I have used it for several video projects and the outcome is very professional.
The people at Techsmith have established excellent tutorials for their product and there is a section devoted to captioning. It has a speech to text capability, syncing with a script as well as manual caption editing.
Techsmith does have a free trial of the software to see how to use it and if you want to buy it. I encourage you to download it and make a video lesson. Don't forget your captions, they are a very important step to making a video accessible for students who need to read subtitles instead of just listening.