It's expensive and difficult to actually do in execution. Seal Team Six is the elite unite of the navy seals, well the Navy built them a "mind gym" where they essentially take advantage of guided meditation, yoga and sensory deprivation tanks, (as well as hypnosis and suggestion, though you would never hear about that) and they have reported that their program is so effective they have been able to teach their seals an entirely foreign language to fluency in regional dialects in a mere five weeks. Now I certainly wouldn't suggest anyone can do this, but there is some precedent.
