Clarifying ambiguous document language: extrinsic evidence may determine the intended meaning of illegible or peculiar terms in writing. Evidence is admissible to establish the meaning of illegible or not commonly intelligible characters and of foreign, obsolete, technical, local or regional expressions, abbreviations, and words used in a peculiar sense, permitting extrinsic proof to resolve ambiguities in a document (for example, determining whether a written term like 'mods' refers to models or modelling tools).