All human languages use exhaled pronunciations and not inhaled pronunciations ("inhalation" i.e. breathing is talked about in phonetics as using "ingressive lung air": read a basic speech and hearing science textbook to understand the mechanics of inhalation, for example Minifie, Hixon & Williams 1973). So tonal languages, specifically, do as well. It is difficult to speak while inhaling, it doesn't sound right, and you can't do it for very long.
Air can flow into the mouth because of negative pressure relative to atmospheric, and this happens systematically in the production of clicks and implosives, where the oral cavity is sealed with the tongue of larynx and then a slight vacuum is created, resulting in brief in-flowing of air into the mouth. This last for maybe some hundreds of milliseconds. Ordinary speech involves egressive lung air and lasts for a number of second between inspirations.