Researchers at Germany's Karlsruhe Institute of Technology (KIT) have developed a method for mobile phones to convert silent mouth movements into speech. The technology is based on the principle of electromyography, that is the acquisition and recording of electrical potentials generated by muscle activity. This muscle activity is measured in the face and converted into speech.

An example is soundless calling.

The user can speak into the phone soundlessly, but is still understood by the conversation partner on the other end of the line. As a result, it is possible to communicate in silent environments, at the cinema or theater, without disturbing others. Another field of use is the transmission of confidential information.

For the transmission of passwords and PINs, for example, users can change seamlessly to soundless language and, hence, transmit confidential information in a tap-proof manner.

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据新华社消息 德国汉诺威国际信息及通信技术博览会2日展出一种“无声电话”，可把嘴唇活动即时转化为电脑发声。使用这种电话，人们无需发声就能让电话另一端的人听清说话内容，避免喋喋不休“电话粥”打扰他人。

这种电话由德国卡尔斯鲁厄技术学院研发，利用肌电描记术监测人讲话时肌肉细微活动，把它们转化为电脉冲后变为电脑发声。这一过程中，“讲话者”无需发出任何声音。

“无声手机”用途广泛。它可以帮助因疾病或意外失声者与他人交流，还能让你瞬间成为能讲多国语言的“牛人”。

万德说：“讲话者在电话一端无声地‘讲’本国语言，电话另一端可以听到经过翻译后的另一国语言。”

不过，眼下这种技术只适用于英语、法语和德语。研究人员希望，“无声手机”能在5年至10年内投入市场。