The semiotization of an element of performance occurs when it appears clearly as the sign of something. Within the framework of the stage or the theatrical event, all that is presented to the audience becomes a sign that "wishes" to communicate a signified. The Prague Circle was the first to theorize about this basis of the semiological approach: "on the sate things that play the part of theatrical signs can in the course of the play acquire special features, qualities, and attributes that they do not have in real life" (BOGATYREV 1938; in MATEJKA and TITUNIK 1976, 35-36). "All that is on the stage is a sign" (VELTRUSKY 1940; 1946,84).
The process of semiotization takes place as soon as we integrate a sign into a signifying system and establish its aesthetic function. The stage becomes the site of a symbolic action by differentiating itself from the real world.
But semiotization exists only in relation to a reality which itself does not turn into a sign, and can lead at any time to a desemiotization: "On stage, everything can also stop becoming a sign, can undergo a desemiotization" (ALTER 1982, 111). This occurs whenever the audience has the feeling of witnessing a real event: an incident in the unfolding of the performance, an error in timing, a break in the acting, an erotic perception on the part of the spectator, or an interest in the actor as a star or a person (rather than the character).
The dialectics between semiotization and desemiotization is, in short, quite specific to theatre: we take real "objects", human beings, props, space and time to make them mean something other than themselves and construct a fiction. No wonder that finally we confuse the thing with the sign, stage reality with that of the other stage where the fiction is presumably taking place.
From Dictionary of the Theatre: Terms, Concepts, and Analysis by Patrice Pavis