objects in the world are not 'true' or 'false.' let's take a classic example:
the sky is blue.this is a pretty widely accepted fact. i don't think any poststructuralists would argue with it, and i don't think i want to, either. but here's the key: in order to widely accept it, in order to declare it as fact, we have to first communicate about it. making an observation about the sky and saying 'the sky is blue' are two very different things.
even an internal concept that the sky is blue is linguistic, because 'blue' and even 'sky' are defined by their conventional uses. 'the sky is blue' might be understood as 'that which we have constituted as a totality called 'the sky' appears to correspond to the hue i have been taught to call 'blue.'' and of course, every term i've used in that expansion could be expanded itself.
for communication to be sucessful, its participants must begin with certain mutual understandings. some of the most basic of these are the names of colors and objects in the world. 'the sky is blue' is not a pure statement of truth because it is always mediated by these categories and assumptions.
likewise, the 'truth' of the statment is mediated by a particular concept of truth: that which is universally agreed upon; that which is measurable by instruments; that which can be recorded. there MAY be an objective truth regarding the color of the sky, but in order to AGREE on it, we HAVE to communicate about it. and in order to determine whether 'the sky is blue' is true, we have to have already agreed about what 'truth' means.