Dual-route hypothesis to reading aloud

The dual-route theory of reading aloud was first described in the early 1970s. This theory suggests that two separate mental mechanisms, or cognitive routes, are involved in reading aloud, with output of both mechanisms contributing to the pronunciation of a written stimulus.

Routes

Lexical route

The lexical route is the process whereby skilled readers can recognize known words by sight alone, through a "dictionary" lookup procedure. According to this model, every word a reader has learned is represented in a mental database of words and their pronunciations that resembles a dictionary, or internal lexicon. When a skilled reader sees and visually recognizes a written word, they are then able to access the dictionary entry for the word and retrieve the information about its pronunciation. The internal lexicon encompasses every learned word, even exception words like 'colonel' or 'pint' that don't follow letter-to-sound rules. This route doesn't enable reading of nonwords (e.g. 'zuce'), though some phonological output can still be produced by matching the word to an approximation in the lexicon (e.g. 'sare' activating visually similar known words like 'care' or 'sore'). There is still no conclusive evidence whether the lexical route functions as a direct pathway going from visual word recognition straight to speech production, or a less direct pathway going from visual word recognition to semantic processing and finally to speech production.