Human language<unk>  takes place whenever a reader or listener processes a language utterance, either in isolation or in the context of a conversation or a text. 
Many studies of the human language<unk>  process have focused on reading of single utterances<unk> s) without context. Extensive research has shown, however, that language<unk>  is affected also by context preceding a given utterance, as well as many other factors.<unk>  has to deal with ambiguity in spoken and written utterances, for example lexical, structural, and semantic ambiguities.  Ambiguity is ubiquitous, but people usually resolve it so effortlessly that they don't even notice it. For example, the<unk>  Time flies like an arrow has (at least) the interpretations Time moves as quickly as an arrow, A special kind of fly, called time fly, likes arrows and Measure the speed of flies like you would measure the speed of an arrow. Usually, readers will be only aware of the first interpretation.
Instances of ambiguity can be classified as local or global ambiguities. A<unk>  is globally ambiguous if it has two distinct interpretations. Examples are<unk> s like Someone shot the servant of the actress who was on the balcony. (was it the servant or the actress who was on the balcony?) or The cop chased the criminal with a fast car. (did the cop or the criminal have a fast car?). Comprehenders may have a preferential interpretation for either of these cases, but syntactically and semantically, neither of the possible interpretations can be ruled out.
Local ambiguities persist only for a short amount of time as an utterance is heard or writtenand are resolved during the course of the utterance, so that the complete utterance has only one interpretation. Examples include<unk> s like The critic wrote the interview was enlightening, which is ambiguous when The critic wrote the book has been encountered, but was enlightening remains to be processed. At this point, the<unk>  could either end, stating that the critic is the author of the book, or it could go on to clarify that the critic wrote something about a book. The ambiguity ends at was enlightening, which determines that the second alternative is correct.
When readers process a local ambiguity, they settle on one of the possible interpretations immediately, without waiting to hear or read more words that might help decide which interpretation is correct (this behaviour is called incremental processing). If they are surprised by the turn the<unk>  really takes, processing is slowed. This is visible for example in reading times. Locally ambiguous<unk> s therefore have been used as test cases to investigate the influence of a number of different factors on human<unk>  processing. If a factor helps readers to avoid difficulty, it is clear that this factor plays a factor in<unk>  processing.
Sentence comprehension
Semantic memory
Information processing
Amodal perception
Body memory
Speech communication
Visual thinking
Face perception