Synesthesia

1. Synesthesia

Synesthesia is a neurologically-based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.

http://en.wikipedia.org/wiki/Synesthesia

2. grapheme-color synesthesia

Grapheme → color synesthesia is a form of synesthesia in which an individual's perception of numbers and letters is associated with the experience of colors.

http://en.wikipedia.org/wiki/Grapheme-color_synesthesia

3. ordinal-linguistic personification   

Ordinal-linguistic personification is a form of synesthesia in which ordered sequences, such as ordinal numbers, days, months and letters are associated with personalities.

http://en.wikipedia.org/wiki/Ordinal_linguistic_personification

4. number-form synesthesia

A number form is a mental map of numbers, which automatically and involuntarily appears whenever someone who experiences number-forms thinks of numbers.

http://en.wikipedia.org/wiki/Number_form

5. sound-color synesthesia

In sound–>colour synesthesia, individuals experience colors as a response to music/sounds. Sound–>colour synesthesia can be further broken down into two categories, “Narrow band” and “Broad band” sound->colour synesthesia.

Narrow band AKA music–>colour synesthesia – When music elicit different shades, hues brightness of colours relative to the tones, notes or even instrument played. Some examples would be, a note of a higher pitch would evoke brighter colours,  and music played from a harp could make an individual see gold.

Broad band synesthesia – Besides music, individuals will be able to see colours from hearing sounds of the ordinary (ringing of alarm clocks, people walking, construction, birds flying).

http://undacovabear.wordpress.com/2009/02/08/sound-colour-synesthesia/

6. lexical-gustatory synesthesia

Lexical → gustatory synesthesia is one of the rarer forms of synesthesia, in which spoken or written words evoke vivid sensations of taste, sometimes including temperature and texture.

http://en.wikipedia.org/wiki/Lexical-gustatory_synesthesia