Semiotic transducer.

Semiotics is the study of constructing meaning. When you look at a stop sign, what do you see? A colored shape. You recognize that as a red octagon, then a metal sign with words, a sign saying "STOP", and a street sign indicating that you need to stop and allow other drivers the right of way. That is a semiotic process.

With semiotic transduction, one's ability to make meaning from things is altered. It could be anything from inverting meanings (a person takes every signal to mean the opposite of what it should) to halting understanding (a person cannot understand any meaning) to filtering signals (a person cannot understand any signal relayed to them by a man).

Note that this applies to all "signals", or things with meaning. A person with completely disrupted semiotics can understand that there's a big red octagonal metal sheet with markings on it, but it bears no more meaning to them than a tree. All language, gestures, and attempts to make meaning will be affected by the transducer.