This is obvious for pictures but surely applies to a lot of other kinds of information. On the other hand, our inability to think completely in parallel shows that many higher mental functions are carried out in serial. For a robot, a logical language will be most suitable, but some appropriate ascriptions of beliefs and intentions to robots will refer to information represented non-logically. Humans clearly don't use quantificational logic at the pre-verbal level, although we can use it when we have to, and formal logic is often helpful when the information is mathematical. A human starts a sentence and thinks how to continue and finish it as he continues talking.
Humans can preform sentences with some effort.
Vladimir Bukovsky tells about having composed a whole book while in prison and denied paper. This can perfectly well be only be represented by the chemical state of the blood stream. Indeed we don't need anything like a sentence in the memory of a computer to represent the voltage of its battery. We may then sometimes be able to explain some actions as involving logical inference from the virtual sentences. Thinking about an object before one's eyes does not require that it have a name.