It is a bad idea to just assume somethings in the public domain. Copyright, like any intellectual property, is a complicated matter. The copyright depends on when the speech was given, if it was written down, and who gave the speech, among other factors. If the speech was recent, i.e. under current copyright law and was contained in a medium such as video, tape, or some written form then the quote is copyrighted. The courts have deemed fair use is okay if the purpose is for educational reasons, such as in papers or educational books, however a game likely does not meet this fair use. So you need to use quotes before the copyright law protected speeches, or ones old enough such that the copyright has ran out. Further, different countries have different timelines and rules for copyright protection, so you need to check where the quote was from. I am unsure about who owns the copyright in the instance that someone who is British gives a speech is India for a fee, it may get complicated. Also, who gives the speech also matters. Any work created by an employee of the United States Federal Government while in the course of performing their official duties is automatically in the Public Domain under the terms of Title 17, Chapter 1, Section 105 of the US Code. This would of course include speeches given by U.S. Presidents and U.S. Military personnel. Same goes for the British Crown Copyright which fall into the Public Domain fifty years after they are created. Your best bet is use old quotes for now and get some quick legal advice from a copyright attorney (or research it for yourself) about the timelines for the protection of speeches in different countries. If the quotes are from a book or other printed source you are more likely to encounter lawsuits, such as a quote from the first 5 pages of Harry Potter.