Sleep Well, Speak Well

Author: Kendra Wormald, Reg. CASLPO Speech Language Pathologist
Date: Wednesday, June 11, 2025

Table of Contents

• Expression

  • Word Finding

  • Fluency and Articulation

• Comprehension

• Critical thinking

• Anxiety and Communication  

• Emotion Expression and Discrimination

• Dopamine Functioning

• Attention 

• Memory 

• Does Quality of Sleep Matter? 

• Conclusion 

• References

Expression

With inadequate sleep quality and quantity, our ability to express our thoughts, emotions and desires, is reduced. Areas such as:
(Ben-Aharon et al., 2023)

Word Finding: The ability to ‘find’ or recall the correct word from memory during speech tasks. 

Sleep deprivation slows down neural communication systems and functions necessary to find and retrieve words. You may experience more “tip-of-the-tongue” moments, using more filler words and having to awkwardly pause. The flow of your message is disrupted, making you sound less confident, knowledgeable and may signal others to interject. 

Examples:
Sleep-deprived utterance: Can you uh, flip onnnnn the food warmer?
Not sleep-deprived utterance: Can you please turn on the oven? 

Fluency and Articulation: This area refers to the ability to speak with smoothness, rhythm and consistent speed. When well-rested, our brains can coordinate thoughts and the subsequent motor functions (i.e put your mouth and tongue in a specific shape, with specific pressure and specific timing) that are needed in order to speak clearly both in our message and our speech sounds. Without enough sleep, the flow of your communication will likely suffer. This may look like stuttering, repeating yourself, slurring and mumbling, false starts, blending words, hesitations and reduced response time. 

Examples:
Sleep-deprived utterance: I need to, I need to go to the… store 
Not sleep-deprived utterance: I need to go to the store.

Comprehension

Reduced sleep and fatigue can make hearing others accurately and comprehending or understanding their words and intended message more difficult (Zhou et al., 2023; Holding et al., 2019). You may find yourself asking people to repeat themselves, needing more time to process what someone has said, and challenges picking up on sarcasm and emotion.

Critical Thinking

When you sleep, your brain isn’t just ‘off’ and resting, it’s processing and organizing information. Sleep supports critical thinking skills specifically by clearing out clutter, helping the brain filter out irrelevant information (Sleep Foundation, n.d.). Have you ever felt as if your brain is ‘full’ or that you feel ‘scatterbrained’? Ask yourself if you slept well the night before. 

We use critical thinking throughout our day in several large and small ways. This is the ability to objectively analyze, evaluate and bring information together to generate a logical and clear judgement.

Examples: 

1. Handling a complaint: Analyzing feedback, assessing the root cause, developing and implementing a plan.
   

2. Deciding what to eat: Assessing what you have available at home, what’s in line with your dietary goals, and whether you have enough time to make it.
   

3. Team Collaboration: Assigning roles, delegating tasks, problem solving, adapting to change.
   

4. Facilitating Meetings: Closing a deal at work with stakeholders, conducting an interview or facilitating a discussion about a raise.

Sleep also deepens logical thinking, fact recall, and strengthens connections between ideas (Sleep Foundation, n.d.). These skills support our understanding of the world, such as what a word or concept means or how to do a skill more effectively. Think of sleep (as well as repetition of skills) as laying down bricks, one by one - until the connection (skill, concept) doesn’t need any reinforcement and can ‘stand’ on its own. You can imagine how these tasks may not turn out favourably for you, when critical thinking is impaired. 

Anxiety and Communication

Sleep deficit can also impact levels of anxiousness,  increasing as much as 30%. We’ve all felt anxious about a conversation, presentation or meeting with stakeholders and executives. However with limited sleep, these already elevated anxiety levels may increase even more - leading to inconsistent and fast rate of speech, use of filler words (um, uh, ya know), stuttering, repeating yourself, and reduced breath support. (Ben-Aharon et al., 2023).

Emotion Expression and Discrimination

(Ben-Aharon et al., 2023; Zhou et al., 2023)

The ability to express emotion is often impaired while feeling unrested.Communication is not just what we say but how we say it. Prosodic qualities such as rhythm, stress, tempo, pausing, volume and intonation are key communication features that support our ability to express ourselves and our emotions accurately. With reduced sleep, it will be challenging for these qualities to be used effectively and consistently. 

Challenges may also arise when expressing and interpreting body language. For example, imagine your friend Jill is standing with her arms crossed while using a flat tone as she says “I’m so happy for you”. Although she may actually be happy for you, this is likely not how you will interpret it. Rather, it may come across as sarcastic, uninterested or even jealous. The disconnect between messenger and receiver originated from Jill’s uncoordinated verbal and non verbal messaging. Turns out Jill didn’t sleep well the night before but is sincerely very happy for you. 

In addition to having challenges expressing emotion, sleep deprived human brains often have greater difficulty distinguishing between facial expressions (Ben-Aharon et al., 2023). Our tired brains are more likely to rate a neutral facial expression as being more emotionally negative. In conversation, this can lead to misunderstanding, confusion and even distrust. 

Your non-verbals need to match your verbals. You need to sleep well, in order to do this well.

** Understanding the impact of reduced sleep on the following brain functions may be particularly valuable for those with ADHD (Attention-deficit/hyperactivity disorder).  

Dopamine Functioning

Dopamine is a neurotransmitter that plays a key role in motivation and reward, and learning and memory among others - and is known as the ‘feel good’ chemical. 

Chronic lack of sleep will reduce the dopamine receptors ability to do their job - therefore dulling its impact.

1. Reward Sensitivity: The reactivity and tendency to respond to reward-related stimuli. Sleep reduction may increase reward seeking behaviours, without full consideration of consequences. This may look like interrupting in conversation to feel heard, prioritizing your own success over team collaboration, focusing on hitting targets, forgetting about the ‘human’ part of communication, and not asking questions when needing help in order to protect your reputation.
   

2. Risk Taking: Reduced sleep can lead to reduced inhibitory capacity, i.e. the ability to stop a behavior - or shifting acceptability rating of engaging in a risk. This may translate into not using inappropriate language and tone when angry with your coworkers, boss, or partner. 
   

3. Impulsivity: Acting quickly and without thorough consideration of consequences is heightened with a shorter sleep duration. You may interrupt in conversation more which can be interpreted as rude or uncaring. Or maybe you share irrelevant information not adding to the brainstorm meeting, or not thinking through a response before responding in an interview. 

Attention

Attention is an umbrella term that captures how we actively concentrate, select and ignore stimuli.  An unrested brain can significantly impact your attention, especially if at your baseline - this is already a challenge.

Attention challenges may result in:
(Krause et al.,2017; Wamsley, 2019)

• Depleted alertness levels 

• Impaired concentration

• Increased  reaction times (i.e not thinking things through first) 

• Inability to sustain focus in a conversation and miss valuable information or appear uninterested 

• Inability to sustain focus on a task resulting in not meeting deadlines 

• Challenges with shifting from one task to another such as writing an email and answering a phone call 

Memory

There are different stages of memory. One being when we’re awake as we encode new information into our brain temporality. The second, consolidation, occurs particularly during REM sleep which solidifies and strengthens memories, then to our third memory stage of retrieving information, when we’re awake again.

When we don’t have enough sleep memory is impacted by: 

• Reduced ability to encode information, resulting in challenges learning new information 

• Consolidation is interrupted and not complete, resulting in puzzle pieces of memories - while missing the other half of the puzzle. This may show up as trying to remember what was said by your boss yesterday when reviewing your slide deck draft, or not being able to recall a concept you were meant to debrief your team on on behalf of your coworker.

• Retrieval of memories is impaired as if you’ve lost the lock to the box of new ideas from yesterday and you’re using a crowbar to get a few out. 

Working memory is a key player in your ability to remember what you and others had just said at the same time as planning what to say next. Forgetfulness and challenges with topic maintenance are often prevalent with reduced rest.

Does Quality of Sleep Matter?

It absolutely does. It is necessary to go through all sleep stages for optimal rest and cognitive functioning (Kohyama et al., 2021; Evie Team, 2023)

REM sleep (rapid eye movement sleep) is a phase of the sleep cycle of high brain activity is necessary for:

• Processing information

• Processing and regulating emotions 

• Enhancing creative and flexible thinking

• Consolidating memories

• Organizing new and old information

• Connecting unrelated ideas, supporting problem solving 

Conclusion

By now you’ve learned that no matter how good you are at cognitive or communication skill, if you don’t get enough good quality sleep - you likely won’t be performing at your best. Support can be sought by a Doctor and Speech Therapist.

References

• Ben-Aharon, A. (2023). The link between sleep and speech – communication skills. Great Speech. https://www.greatspeech.com/the-link-between-sleep-and-speech/#:~:text=Sleep%20and%20Communication%20Skills,ability%20to%20properly%20articulate%20ourselves.

• Evie Team (2023). Quality vs Quantity of Sleep: Which Is More Important? Evie Ring. https://eviering.com/blogs/news/sleep-quality-vs-quantity

• Holding, B. C., Sundelin, T., Lekander, M., & Axelsson, J. (2019). Sleep deprivation and its effects on communication during individual and collaborative tasks. Scientific Reports, 9(1), 3131. https://doi.org/10.1038/s41598-019-39271-6

• Kohyama, J. (2021). Which is more important for health: Sleep quantity or sleep quality? Children, 8(7), 542. https://doi.org/10.3390/children8070542

• Krause, A. J., Simon, E. B., Mander, B. A., Greer, S. M., Saletin, J. M., Goldstein-Piekarski, A. N., & Walker, M. P. (2017). The sleep-deprived human brain. Nature reviews. Neuroscience, 18(7), 404–418. https://doi.org/10.1038/nrn.2017.55

• Sleep Foundation. (n.d.). How Lack of Sleep Impacts Cognitive Performance and Focus. Sleep Foundation. https://www.sleepfoundation.org/sleep-deprivation/lack-of-sleep-and-cognitive-impairment

• Wamsley, E. J. (2019). Memory consolidation during waking rest. Neurobiology of Learning and Memory, 160, 1–7. https://doi.org/10.1016/j.nlm.2018.03.008

• Zhou, Y., Li, H., Liu, X., Chi, X., Gu, Z., Cui, B., Bergquist, J., Wang, B., Tian, G., Yang, C., Xu, F., & Mi, J. (2023). The combination of quantitative proteomics and systems genetics analysis reveals that PTN is associated with sleep-loss-induced cognitive impairment. Journal of Proteome Research, 22(9).a

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