Evidentiality is linguistic reference to information source, that is, how a speaker knows the information in his statement (e.g., through ‘seeing’ or ‘being told about’ it). All languages have a way of expressing evidentiality. However, in languages such as Turkish, this feature is obligatory in the grammar. How does our brain cope with several information sources in the language, especially when one speaks two languages? To answer this, we use EEG to record brain activity, as well as, eye-tracking and other experimental methods during sentence processing in Turkish. In addition, we study the loss of evidential forms in individuals with aphasia, a speech disorder that renders normal communication impossible due to damage to language areas of the brain. This project will not only show how evidentiality is processed in the brain, but also will reveal how bilinguals cope with it.