While all languages can express epistemic awareness regarding the source of a message's content, Romance languages lack mandatory indicators. Such markers enhance confidence in sources such as journalism by specifying whether information is based on experience, hearsay or inference. Although they are not apparent, we can elucidate this by explicitly stating the origin of our knowledge, typically to lessen responsibility. Over the past 30 years, studies have explored markers of knowledge origin, yet consensus on evidentiality markers and effective research methods remains elusive. This book takes a comparative approach, focusing on content as well as linguistic forms such as adverbs, adjectives, verbs and tenses. Evidentiality provides non-predicative information and distinguishes between sources of information such as personal observation, external communication or inference. Communication generally lacks differentiation of sources, resulting in broad evidential-epistemic marking.