Copyright protects a specific orginal expression, including a written work. Copyright inures, or comes into being, as soon as you create the expression; technically, you do not have to register it to protect it, though registration enhances the protection substantially. If the slogan or sentence is not as original as you think, however, it may not be copyrighted--copyright only protects original expressions.Most importantly therefore, you cannot generally copyright something as short as a single sentence or slogan--they are so short as to by law not present the requisite originality, since short sentence or phrases are almost certainly in use and/or previously created by others.Trademark protects a slogan, design, name, etc. which is used to identify goods or services. You cannot trademark something which is not associated with goods or services, and you can only trademark something actually being used in commerce, or which will be used in commerce in the near future.Therefore, from what you write, it is very likely that neither copyright nor trademark protection is available to you, though you could call the U.S. Patent and Trademark Office (PTO) to get guidance from them--they handle copyright as well. Try calling 800-786-9199.