The English-Xhosa Dictionary for Nurses (EXDN) is a bilingual, unidirectional printed dictionary in the public domain, with English and isiXhosa as the language pair. By extending the digitisation efforts of EXDN from a human-readable digital object to a machine-readable state, using Resource Description Framework (RDF) as the data model, semantically interoperable structured data can be created, thus enabling EXDN's data to be reused, aggregated and integrated with other language resources, where it can serve as a potential aid in the development of future language resources for isiXhosa, an under-resourced language in South Africa. The methodological guidelines for the construction of a Linguistic Linked Data framework (LLDF) for a lexicographic resource, as applied to EXDN, are described, where an LLDF can be defined as a framework: (1) which describes data in RDF, (2) using a model designed for the representation of linguistic information, (3) which adheres to Linked Data principles, and (4) which supports versioning, allowing for change. The result is a bidirectional lexicographic resource, previously bounded and static, now unbounded and evolving, with the ability to extend to multilingualism.Information 2018, 9, 274 2 of 30 into a simple digital resource, typically as images in JPEG format. However, by retrodigitising the artefact, converting it from a simple digital resource to a complex digital resource, it has the potential to become machine-interoperable. The form of complex digital objects can vary, with examples including: a collection of XML files; the same content but as HTML files with semantic markup to describe the content therein; as a dataset stored in a relational database or as Resource Description Framework (RDF). For the latter example, RDF "is a framework for representing information in the Web", published by the World Wide Web Consortium (W3C), where data is described in short statements, called triples, which are of the form subject-predicate-object [9]. A subject can be an internationalised resource identifier (IRI) or a blank node; an object can be an IRI, blank node, or a literal; and a predicate can be an IRI only [9].The lexical entry Abdomen can be expressed in the following short statements:Abdomen is a lexical entry.Abdomen is a word.Abdomen is a noun.Abdomen is an English term.Using Turtle syntax, a human-readable serialisation of RDF, the same short statements can be described in RDF:
SubjectPredicate Object :abdomen :isA :lexicalEntry ; :isA :word ; :isA :noun ; :isLanguage :English .These short statements are visualised in Figure 1, using node-edge-node structure. Information 2018, 9, x FOR PEER REVIEW 2 of 29Despite EXDN being published more than seventy-five years ago, as a language resource for an under-resourced indigenous African language, its content is still of value [1] (p. 1). EXDN is in print form, bounded and static, and by digitising the dictionary, it is converted from an analogue resource into a simple digital resource, typically as images in JPEG format. Howev...