Beware of generalisations like

• Blind students all know Braille and have excellent memories.  
• Deaf students only use sign language (which is universal)
  and are very good at drawing.
• A wheel chair user can/can't ...

Reality is a whole range of possible combinations. 

Skills and preferences depend on many factors such as

• the extent of the impairment/ disability: Did you know that 95% of visually impaire people CAN see a little; under 5% are totally blind and see not light at all.  
• the start :  if from birth, the person will have known no other way, and may not have certain concepts - so ask what they know/ understand.  If the condition started later, there may be memories and skills acquired before the start (a child who loses their hearing after they have learnt to speak may appear 'normal'....).  A condition may happen suddenly (after an accident, or meningitis or...) and is unexpected; or a gradual progress may mean the person doesn't at first notice that they are less able to do what they used to do, until a particular event shows the difficulty.  In both cases, the person - and their family-friends - need time to accept the situation.  This is not simple, may take years, and progress in stages. 
• Coping mechanisms and attitudes. 
• Opportunities: A child at a school for the blind may become fluent in Braille, but another who is mainstreamed may never know about Braille and learn totally by ear.  The first will be able to learn spelling easily, the second will be used to learning with non-disabled people: neither is perfect, both have advantages and disadvantages.   

A student is disabled if their condition (physical, physiological, psychological) disadvantages them compared to non-disabled learners.

 Note: Many disabilities are unseen .   You cannot see diabetes, dyslexia, deafness, thalassemia (sickle cell anemia), etc.  You cannot see pain (glaucoma), tiredness (cancer treatment, neurological conditions), or stress (psychological effect of a new or progressive condition). Most students prefer to 'appear normal', being just like everyone; many declare a special need only when they need different ways (cannot manage with regular methods). A student needs courage to be able to talk about this.  They need to trust the teacher will respect their needs.