I use fluorescent photo lights with photo-umbrellas. Soft boxes have some advantages, but are more bulky to store. If I had a place to store them, or could leave them set up in a studio all the time, I would probably use soft boxes.
It is a joy to work with fluorescents, and leave behind the heat, glare, and burn risk of halogen lights. I use daylight balanced (5500˚K) 45W bulbs, which have a light output level similar to a 150W incandescent. One bulb is usually not bright enough, so I use a four-socket adapter in each umbrella, which lets me employ one, two, three, or four bulbs at a time in each umbrella. The color index (CRI) of 91 for these bulbs is better than most fluorescents, and I have found it to be quite acceptable. I've seen fluorescent photo bulbs up to 105W, but the color index is not as good, and the lumen output per Watt is lower, so I prefer to use more of these 45W bulbs.
I usually use two umbrellas at 45˚ left and right of the subjects, against a seamless paper or cloth backdrop. For sign language, I like a light-to-medium blue backdrop, since it shows sufficient contrast with both light and dark skin tones of the people signing. It's often useful to have an additional light shining on the backdrop, to soften the subject's shadows on the backdrop and increase visual separation between the subjects and the background. However, ambient room light is sometimes sufficient for that aspect.
This kind of a setup gives a very soft look with mild, even contrast. This may be too flat for fashion photographers and Hollywood studios, but I think it works very well for instructional materials. It means that the subjects can move around a bit, without throwing the lighting way off, or getting unacceptable shadows on the faces.
ALZO Digital Full Spectrum Light Bulb - ALZO 45W Photo CFL 5500K 91 CRI, Daylight balanced, pure white light, 2800 Lumens, Case of 4
http://www.amazon.com/gp/product/B00198U6U6/ref=oh_details_o05_s00_i00Photo Basics 413 4-Socket Adapter
http://www.amazon.com/gp/product/B0028K2TXQ/ref=oh_details_o04_s00_i00
Derek