Overview
ISO 24615-2:2018 - Language resource management - Syntactic annotation framework (SynAF) - Part 2: XML serialization (Tiger vocabulary / ISOTiger) defines an XML-conformant serialization of the ISO 24615‑1 SynAF meta‑model. The standard specifies a language- and theory‑independent XML format (based on TigerXML) to promote interoperability between syntactic annotations, treebanks, syntactic parsers and language processing components.
Key topics and technical requirements
- Meta-model instantiation: Concrete XML element and attribute names mirror the ISO 24615‑1 meta‑model (graph, nodes, edges, annotations).
- Graph-based representation: Syntactic annotations are modeled as graphs G = (V, E, A) with nodes (terminals and non‑terminals), directed edges and feature-value annotations.
- XML vocabulary (ISOTiger): Core elements and conventions include:
- (segment) containing one or more elements
- with elements (terminal nodes)
- with elements (non-terminal nodes)
- elements as children of or with @target to reference nodes
- Attribute conventions such as @word for token text
- Primary data handling: Two allowed representations
- Sequential representation - primary data included inside elements (single XML file)
- Standoff representation - primary data referenced externally (e.g., MAF files), enabling modular architectures
- Annotation tagsets and features: Tagsets expressed via Feature and FeatureValue constructs; categories may reference standardized data categories (DatCatInfo) via URIs in compliance with ISO 12620.
- Namespaces and interoperability: XML elements use the CLARIN SynAF namespace (http://www.clarin.eu/standards/ns/synaf), and the format is coordinated with related ISO frameworks.
Applications and users
ISO 24615-2:2018 is practical for:
- Corpus linguists and treebank curators building or exchanging syntactically annotated corpora
- NLP engineers and tool developers implementing parsers, converters or visualization tools that must interoperate with standard treebanks
- Digital humanities projects that need standardized syntactic markup for multilingual resources
- Research groups comparing annotation schemes or combining annotations from different sources
Benefits include improved reuse of syntactic annotations, easier tool integration, and language/theory neutrality for syntactic data exchange.
Related standards
Keywords: ISO 24615-2:2018, SynAF, ISOTiger, TigerXML, XML serialization, syntactic annotation, treebank, language resource management, standoff representation, sequential representation.