Dyslexia is a neurodevelopmental difference that primarily affects the ability to read and spell accurately and fluently. It is a language-based learning disability rooted in how the brain processes written information. Although the most visible symptoms involve decoding words on a page, dyslexia is fundamentally connected to language processing, which includes spoken language. This means that the core differences in the brain that make reading difficult can also influence how a person uses or understands speech.
The Root Cause: Phonological Processing
The connection between reading difficulties and spoken language lies in a shared underlying cognitive challenge: a deficit in phonological processing. Phonological processing is the ability to recognize, understand, and use the sound structure of a language. This includes being able to identify, remember, and manipulate the discrete sounds, or phonemes, that make up spoken words.
A related concept, phonological awareness, is a person’s explicit sensitivity to the sound structure of words, which is a significant predictor of reading success. For example, phonological awareness allows a person to count the syllables in a word, identify rhyming words, or know that the word “cat” is made up of the distinct sounds /c/, /a/, and /t/. This skill is essential because reading requires mapping written letters, called graphemes, to these underlying speech sounds.
When phonological processing is weak, it creates a bottleneck for both reading and speaking. The difficulty is not in hearing the sounds, but in the brain’s ability to efficiently process and segment those sounds for language use. This deficit links the struggles with decoding written words to the challenges that appear in spoken communication.
How Spoken Language is Affected
The challenge in processing the sounds of language manifests in several observable ways during spoken conversation. One common effect is word retrieval difficulty, sometimes called anomia, or the “tip-of-the-tongue” phenomenon. The person knows the concept they want to express but struggles to quickly access the correct phonological code—the sounds needed—to form the word, leading to hesitations and pauses.
This retrieval issue is related to language processing rather than a problem with memory for the meaning of the word itself. In conversation, this can result in using filler words like “um” or “like,” or substituting a less-specific word for the precise one intended. The effort to retrieve the correct sequence of sounds can disrupt verbal fluency, making speech feel less spontaneous and more labored.
Another manifestation is difficulty accurately pronouncing long or multi-syllabic words, such as “aluminum” or “statistics”. Since the person has trouble segmenting and manipulating individual phonemes, they may struggle to coordinate and sequence the sounds within a complex word. This is not a physical inability to move the mouth, but rather an issue with the internal linguistic blueprint for the word’s sound structure.
Furthermore, dyslexia can sometimes be associated with broader expressive language difficulties, including trouble with syntax and verbal organization. A person may struggle to structure their thoughts coherently or use complex grammar when speaking, even if their understanding of language is strong.
Distinguishing From Articulation Disorders
It is important to differentiate the speech challenges related to dyslexia from traditional articulation disorders, which are motor-based. An articulation disorder, such as a lisp, is a physical difficulty in producing a specific speech sound due to problems with the movement of the tongue, lips, or jaw. The person knows what sound they want to make, but the physical mechanism of speech production is impaired.
In contrast, the spoken language issues linked to dyslexia are not rooted in motor control but in the brain’s linguistic processing system. The difficulty is in the organization and sound-sequencing of the word before the mouth even begins to form it. For example, a person with dyslexia might mispronounce a long word because their phonological system cannot accurately hold and sequence all the sounds, not because they cannot physically make the sound itself.
While some individuals with dyslexia may also have a history of mild speech sound production difficulties, the core linguistic deficit is distinct from a motor speech disorder. This difference means that standard speech therapy focusing only on the physical mechanics of sound production may not address the underlying cognitive cause of the dyslexia-related spoken language issues.
Targeted Interventions and Support
Interventions for spoken language issues related to dyslexia must target the underlying phonological processing deficit, thereby helping both reading and speech simultaneously. The most effective approach for this is Structured Literacy, which is explicit, systematic, and multisensory. This method focuses intensely on building phonological awareness and connecting sounds to symbols.
Specialized speech-language pathology interventions often incorporate activities that train the brain to manipulate sounds. These activities might include blending sounds to form words, segmenting words into individual phonemes, and working with rhyming and rhythm. These exercises strengthen the internal representation of sound structure, which is the foundation for all language use.
Multisensory techniques are frequently used, such as having a person trace a letter while saying its sound and simultaneously hearing it. This engagement of visual, auditory, and kinesthetic senses helps solidify the sound-to-symbol connection and improve word retrieval. Assistive technology, such as speech-to-text tools, can also support communication by allowing the person to bypass the difficulty of translating thoughts into written words and focus on organizing their verbal expression.