Lip-reading—the technique of understanding speech by interpreting the lip movements of a speaker—is a tool primarily used by deaf people to understand those who do not know sign language. By analyzing the movements, shape, and position of the lips, mouth, and tongue, deaf people are able to deduce which units of sound are being produced and thereby reconstruct each word.

In fact, those of us who do not suffer from impaired hearing also use lip-reading, albeit unconsciously. When we speak to someone, we use facial clues as well as the shape of someone's mouth to aid comprehension, particularly in environments with loud background noise.

One of the biggest drawbacks to relying solely on visual cues for lip-reading is that many sound units, or phonemes, are created by very similar lip movements. In reality, only about 30% of sounds in English can be definitely distinguished by sight alone. This is why understanding the context of a conversation is often vital to effective lip-reading. The words "meat," "beat," and "peat," for example, all have the same visual cue; however, if encountered in the sentence "The Chicago Bulls [blank] the Knicks last night," only one of these three words is possible.

Needless to say, for people who were born deaf, learning to lip-read is a far bigger challenge than it is for those who are already familiar with these sounds. That being said, lip-reading is still not an easy skill to learn, and even when mastered, its effectiveness can be compromised by something as small as a mustache or a shadow.

If you're interested in learning to lip-read, here are some tips to get you started: Practice focusing on other people's lips while they're talking; watching the news is especially good for this as anchormen and anchorwomen tend to speak more clearly than normal people. When you start to feel comfortable with this, watch a favorite movie or TV episode with the sound on mute. Try to follow the dialogue just by lip-reading. If the movie has subtitles, you can turn them on to give you a hand if you get stuck!

讀唇術是指「解讀說話者的唇部活動，來理解說話內容的技術」，主要是聽障者用來與不諳手語的人士溝通的工具。聽障者藉由分析說話者唇、口、舌的活動、形狀和位置，可以推測對方的發音，進而組合出每一個字。

事實上，沒有聽力受損問題的人，也隨時都在使用讀唇術，只是沒有意識到而已。當我們與人交談時，會觀察對方的臉部表情和嘴型，幫助我們理解，尤其是周圍環境特別嘈雜的時候。

然而，光靠讀唇取得視覺線索仍有一大缺點，就是許多音的發音唇型非常接近。事實上，只有30% 左右的英文發音能夠僅靠視覺清楚辨識。正因如此，有效的讀唇極度仰賴對話的前後脈絡。舉例來說，meat、beat、peat 這三個字從視覺上看起來是一樣的，不過如果套用在「The Chicago Bulls _______ the Knicks last night.」（昨晚，芝加哥公牛隊 _______ 尼克隊。）就只有一個字符合條件。

不用說，天生耳聾的人學習讀唇術，所面臨的挑戰遠大於早已熟習這些發音的人。儘管如此，讀唇術還是不好學，即便學會，一點小障礙，像是鬍子或陰影，都會讓讀唇的效果大打折扣。

如果你有興趣學讀唇術，這裡有一些小技巧：在他人說話時，練習注意看他們的嘴唇。看新聞對這種訓練特別有用，因為播報員比一般人說得更清楚，你比較不容易讀錯。當你看新聞駕輕就熟之後，就可以開始用靜音模式看你喜歡的電影或電視連續劇，試著讀唇來理解對話內容。如果電影有字幕，也可以在遇到瓶頸的時候，適時開啟字幕！