Hello
As far as I know about sampling regardless it is music or motion picture or any sort of audio or video intellectual creation, I used FairUse for different types of work during my carier as a Producer for McCann Erickson or in my MTV years and that being use of music for illustrating a music promo for a music tv/radio show or movie excerpts for same use but only for movie related shows.
What are you referring to is this "Samples of spoken word - Usually taken from movies, television, or other non-musical media, often used for humorous or atmospheric effect."
Now, from samplinglaw.com
"What about all those songs with samples from movies and TV shows?
Copying someone else's work, even if transmedium, is still infringement. You could get sued for sampling dialogue. However, I could not find one case in any single court of America that dealt with sampling film or TV dialogue in music. That doesn't mean that nobody has ever gotten sued for it. It just means that it never made it into a published court decision. As of now, it's illegal. You may attempt to defend yourself under the Fair Use de minimis use exception (explained in the Fair Use section), but courts have never decided the issue. As Negativland has propounded, "fragmentary", transcontextual use of media should be okay under Fair Use exception. I agree, but there is no legal authority to support it."
But what about that Fair Use term?
Here it is as stated in the US Copyright law: "the fair use of a copyrighted work, including such use by reproduction in copies or phonorecords or by any other means specified by that section, for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. In determining whether the use made of a work in any particular case is a fair use the factors to be considered shall include
(1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
(2) the nature of the copyrighted work;
(3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
(4) the effect of the use upon the potential market for or value of the copyrighted work.
The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors."
or
"How much of someone else's work can I use without getting permission?
Under the fair use doctrine of the U.S. copyright statute, it is permissible to use limited portions of a work including quotes, for purposes such as commentary, criticism, news reporting, and scholarly reports. There are no legal rules permitting the use of a specific number of words, a certain number of musical notes, or percentage of a work. Whether a particular use qualifies as fair use depends on all the circumstances. See FL 102, Fair Use, and Circular 21, Reproductions of Copyrighted Works by Educators and Librarians"
and
"Copyright protects the particular way an author has expressed himself; it does not extend to any ideas, systems, or factual information conveyed in the work.
The safest course is always to get permission from the copyright owner before using copyrighted material. The Copyright Office cannot give this permission.
When it is impracticable to obtain permission, use of copyrighted material should be avoided unless the doctrine of fair use would clearly apply to the situation. The Copyright Office can neither determine if a certain use may be considered fair nor advise on possible copyright violations. If there is any doubt, it is advisable to consult an attorney."
I hope that helped out somehow. Cheers.