Dyslexia is a set of processing difficulties that affect the acquisition of reading and spelling.

In dyslexia, some or all aspects of literacy attainment are weak in relation to age, standard teaching and instruction, and level of other attainments. Across languages and age groups, difficulties in reading fluency and spelling are a key marker of dyslexia. Dyslexic difficulties exist on a continuum and can be experienced to various degrees of severity.

The nature and developmental trajectory of dyslexia depend on multiple genetic and environmental influences. Dyslexia can affect the acquisition of other skills, such as mathematics, reading comprehension, or learning another language.

The most commonly observed cognitive impairment in dyslexia is a difficulty in phonological processing (i.e. in phonological awareness, phonological processing speed or phonological memory). However, phonological difficulties do not fully explain the variability that is observed. Working memory, processing speed, and orthographic skills can contribute to the impact of dyslexia.

Dyslexia frequently co-occurs with one or more other developmental difficulties, including developmental language disorder, dyscalculia, ADHD, and developmental coordination disorder.

Specific learning difficulties are neurological in nature (as opposed to psychological) and impact how an individual manages information input, processing and output.

Such difficulties are independent of intelligence, and frequently run in families. They affect the acquisition and development of literacy, numeracy and/or language skills, and therefore impact learning to varying degrees. Any specific learning difficulty may co-occur with others and be experienced in multiple ways.

Any combination of difficulties may manifest itself in:

• Writing
• Organisation and time management
• Memory
• Processing (audio/visual)
• Reading
• Sensory issues
• Focus and concentration
• Self-management

ADHD is a neuro-developmental condition which often co-occurs with SpLD's

Language & literacy needs refers to the broad spectrum of skills required to understand and communicate in spoken and written language. Reading and listening are known as receptive skills, whereas speaking and writing are productive skills.

While dyslexia is a specific type of neurobiological condition, in which the learner has a core language processing deficit. Dyslexic learners experience difficulties with the printed word. All individuals with dyslexia have specific literacy needs which can be related to phonological processing and decoding.

Language & literacy needs occur on a broader spectrum and cannot be attributed to a single core deficit. The learner may also struggle with oral communication such that it impacts social skills. Not all individuals with language & literacy needs have dyslexia. The less they expose themselves to language (through reading and language-rich talk), the further they will fall behind in their literacy development as their peers continue to accumulate experience with new language through learning.