The article "The Complementarity of Natural and Indexing Languages" by R. Fugmann discusses the importance of representational predictability in literature search systems. The author argues that while natural language is user-friendly, it lacks the predictability needed for effective retrieval, especially for general concepts. In contrast, indexing languages provide high representational fidelity, which is crucial for precision and completeness in retrieval. The article highlights the limitations of natural language in handling ambiguous and non-lexical expressions, which can lead to incomplete or imprecise results. It also addresses the issue of translation problems and the specificity of indexing languages compared to natural languages. The conclusion emphasizes that both natural and indexing languages can complement each other effectively, with each serving its specific strengths and weaknesses. The key to successful information systems lies in combining these languages where they are most effective, rather than choosing one over the other.The article "The Complementarity of Natural and Indexing Languages" by R. Fugmann discusses the importance of representational predictability in literature search systems. The author argues that while natural language is user-friendly, it lacks the predictability needed for effective retrieval, especially for general concepts. In contrast, indexing languages provide high representational fidelity, which is crucial for precision and completeness in retrieval. The article highlights the limitations of natural language in handling ambiguous and non-lexical expressions, which can lead to incomplete or imprecise results. It also addresses the issue of translation problems and the specificity of indexing languages compared to natural languages. The conclusion emphasizes that both natural and indexing languages can complement each other effectively, with each serving its specific strengths and weaknesses. The key to successful information systems lies in combining these languages where they are most effective, rather than choosing one over the other.