Comprehension occurs as the listener builds a mental representation of the information contained within the language that a speaker is using… the listener's general knowledge and level of cognitive development will have a bearing on the comprehension of the message. To generate an accurate mental representation… it means that the listener has to process the language and the concepts.
In particular, lexical knowledge can affect the perception of phonemes. A number of researchers have found evidence for interactivity in the form of lexical effects on the perception of sublexical units. Wurm and Samuel (1997), for example, reported that listeners’ knowledge of words can lead to the inhibition of certain phonemes. Samuel (1997) found additional evidence of interactivity by studying the phenomenon of phonemic restoration. This refers to the fact that listeners continue to “hear” phonemes that have been removed from the speech signal and replaced by noise. Samuel discovered that the restored phonemes produced by lexical activation lead to reliable shifts in how listeners labeled ambiguous phonemes.
If we recognize words, and perceive speech generally, via our stored memory for linguistic forms, it may also be true that we perceive aspects of the world around us, as presented to us through non-linguistic means, via our stored knowledge of the way the world works. So, we are able to address the phenomenon of ambiguity and further issues in interpretation, concentrating on how the listener arrives at a reconstruction of what the speaker wishes to communicate be.