Used in the place of "yes" yay-eee-s
Expression used to acknowledge a comment that is exceedingly odd or beyond the listeners level of understanding. Also used as a way of providing an answer without actually answering anything. Often one may incorporate a pause as to create the illusion that they are actually thinking of a valid answer or comment. One may also use "yais" as a way of covering up his/her daydreaming while in a conversation. For an example of how to say "yais" properly listen to tom hanks in the movie "The Terminal".
ex. person 1("So do you think it will work?)
person 2(*clueless* "ye.....yais")
ex. person 1("Lets the bed of your truck up with jello to
attract aliens!! It would be sweet!"
person 2(*too tired to call person 1 an idiot* "Yais")
ex. person 1("We are meeting at seven oclock right?")
person 2 (*not willing to answer yes or no* "ye...yais")