Reading Lips

Milhouse: What are they saying?
Bart: I'm not sure.
Milhouse: I thought you said you could read lips.
Bart: I assumed that I could.

—The Simpsons, "Lemon of Troy"

Characters being able to understand what others are saying by reading their lips. Usually an ability of deaf people, though anybody with good eyesight at least can have it.

Can be used when two characters want to communicate silently. Alice wants to give Bob a message, so she mouths it to him. If Played for Laughs, then Bob will reveal that he can't read lips, making the whole thing pointless.

Examples of Reading Lips include:

Anime and Manga

Ghost in the Shell: Stand Alone Complex: in one episode, a Tachikoma reads the lips of the Major and Batou as a Shout-Out to [[2001: A Space Odyssey]]. Subverted because they know they're being watched and have their conversation via wireless communication with their cyberbrains and have a fake conversation for the Tachikoma to lip read leaving them falsely reassured that The Major was merely chewing Bateau out for being too much of a Drill Sergeant Nasty and the Tachikoma weren't being decommissioned.
Soul Eater: Justin Law can read lips, which is good considering he has ear phones on most of the time.
- But he can't understand Shinigami (without removing his earphones) thanks to his mask.

Comic Books

In Avengers Academy #1, Finesse reads Speedball's lips and learns that the students are there because they are the most likely to become supervillains.
Superman used a viewer that gathers "light rays" to see past. As it's all light, superman had to use lipreading to see what was spoken. There was some oddities like blank talk bubbles from some people facing away from viewpoint. How would he know those people were speaking in first place?

Film

In 2001: A Space Odyssey, Dave and Frank lock themselves in a soundproof pod so they can safely talk about the project computer, HAL, who seems to be acting strange. It doesn't occur to them that HAL can read lips...

Literature

Encyclopedia Brown realizes that the thief who "overheard" the owners of a barber shop could do so while sitting under a hair dryer because she could read lips.
In the classic Sci Fi novella E for Effort a couple of guys invent a machine that films historical events (like Napoleon at Waterloo); they hire expeert lipreaders to figure out what exactly the people they film are saying - it comes without audio.
In Judge Dee, Tao Gan mentions that among his many skills of questionable legality, he can read lips (it's easier on children and women than on bearded men).
In the book A Maiden's Grave, a girl only realizes she's going deaf and reading lips to compensate when she "mishears" "Amazing Grace" as "A Maiden's Grave".
At one point in The Malleorean, the heroes have to come up with fairly elaborate ways to hide what they're saying in a city of spies; they've learned that some of the spies are deaf and read lips, so just masking their voices isn't going to work. They take to meeting at night.

Live Action TV

One episode of Monk involved a murderer who could read lips, which is how he managed to "eavesdrop" on a conversation in a building from afar.
The Seinfeld episode "The Lip Reader" centered around this. Jerry was dating a deaf woman who misread his saying "six" as "sex."

Jerry: So we'll swing by and pick you up. How about six? Six is good. You got a problem with six? ... What? What?

Kensi from NCIS: Los Angeles
In The Pretender episode "Flyer", the hero takes lip-reading lessons from a deaf woman in order to be able to figure out a conversation on a piece of surveillance footage.
The Wire has a few scenes with a lip-reader—Herc manages to plant a camera overlooking Marlo's preferred meeting-spot but not a microphone, so he brings one in to tell him what Marlo is saying.
Scrubs: JD zones out and tries to recreate the lip motions so that they can be read.
In The Hardy Boys Nancy Drew Mysteries episode "Silent Scream", a deaf girl finds out about a Las Vegas bomb plot by reading the lips of a man in a phone booth. Of course, the woman, the Hardys, the villains, and the casino owners then spend the rest of the episode passing around the Idiot Ball, but no one's perfect.
The deaf characters in Switched at Birth are proficient at this- namely, Daphne, Emmett and Melody.
Sue in Sue Thomas: F.B.Eye, who is Deaf, uses her lip-reading abilities to do surveillance work for the FBI. The show is loosely based on the real-life Sue Thomas, who was the first deaf undercover investigator for the FBI.

Tabletop Games

Starblazer Adventures, based on the 1970's-80's British science fiction comic book. The Lip Reading stunt allows you to do this.
Dungeons & Dragons. The 2nd Edition Player's Handbook introduced the Reading Lips non-weapon proficiency.
Warhammer 40,000 Roleplay has Lip Reading skill useful both to "overhear" conversations (at least if the speaker doesn't have much facial hair... or gas mask... or an implant replacing the whole jaw) and communicate with someone who also can do so, while saying aloud something else.

Web Comics

Girl Genius has Zeetha creatively using her smiley headband to communicate with Higgs.

Web Original

This is the general principle behind Bad Lip Reading - they read lips, badly, and then put the resulting "lyrics" to music (generally; some shorts based on footage of the 2012 presidential candidates was just read back verbatim, instead). Hilarity Ensues.
Julian Smith as the Bad Dad of "Reading Lips" claims he can do this, but it's incredibly clear he's just making up whatever the subject in question is saying.

Real Life

In practice, lipreading is fairly difficult skill, with around 50-75% success on identifying words and filling in blanks. Not all deaf people could lipread, as some people would assume.
- This is because several different sounds use the same or similar external mouth movements; for example, "elephant juice" and "I love you" look exactly the same.
  - "Aishiteru" (a Japanese form of "I love you") looks the same as the above two English phrases.
At least one deaf basketball team has won this way, as the rival team spoke their plan out loud since they weren't worried about being overheard, unaware that the deaf players could also read lips.