It is called somniloquy. The person talking during sleep is completely unaware of it. Sometimes it may also involve bodily movemnts. Arousals during sleep are often accompanied by increased muscle activity such as in the jaw, which can be a source of teeth grinding. These can be temporary, mostly caused by severe stress,  anxiety, dreams., etc. Avoid excess use of caffiene,  alcohol if having. If you are going through any stressful activities try to come out of it by doing any activitiws that are recreational. If problem persists consult a nearby homoeopathic physician once.