Can we be conscious without language? While we can certainly feel emotions or see colours without speaking, a new critical review suggests that language plays a far more fundamental role in shaping our conscious experience than previously believed.
Researchers from the University of Liège have found that the relationship between these two functions is not a one-way street, but a complex, bidirectional partnership that could change how doctors treat patients recovering from severe brain injuries.
In a paper published in Neuroscience & Biobehavioral Reviews, the team challenges the binary view that language and consciousness are either completely independent or that one is strictly required for the other.
“We have discovered a fundamental distinction between different levels of language processing,” explains Charlène Aubinet, a neuropsychologist at the Coma Science Group and the study’s lead author.
The hierarchy of awareness
The researchers found that the brain handles language in layers. Low-level processes — such as recognising speech sounds or identifying simple words — can occur even when consciousness is “greatly reduced,” such as during deep sleep, under anaesthesia, or in patients with disorders of consciousness.
However, more complex tasks, such as understanding a full sentence or grasping abstract ideas, appear to require a high level of consciousness.
The review highlights that while the brain can automatically detect “deviant” sounds or words while unconscious, the ability to integrate these words into a coherent message (a “high-level” process) generally disappears when consciousness is lost.
Vital sign for coma patients
This distinction has major clinical implications. The study reveals that signs of language processing can sometimes precede and even predict the return of consciousness in patients recovering from a coma.
“This observation… calls for caution in interpreting the absence of verbal responses as a sign of unconsciousness,” Aubinet warns.
The recovery of language often parallels the recovery of consciousness, suggesting that tracking language abilities could provide a vital window into the minds of unresponsive patients.
The inner voice
The study also explores the role of “inner speech”—the little voice in our heads. The researchers suggest that this internal monologue is not just noise, but a tool that shapes self-awareness and “metacognition,” the ability to reflect on our own thoughts.
Evidence from patients with aphasia — a language disorder resulting from brain damage — supports this. Those with severe language impairments often struggle with non-verbal cognitive tasks and self-reflection, indicating that language acts as a “scaffold” for higher-level conscious thought.
“While language does not create consciousness, it nevertheless seems to have a bidirectional, profound and still mysterious relationship with it,” the researchers conclude.
