A wide variety of methods exist in the field of accident investigation. The challenge to find the cause for each and every accident has perpetuated a complicated and fundamental debate. In spite of the different paradigms, the many branch specific investigation methods, decades of accumulated and documented accident investigation experience, the diversity in taxonomy of causal factors, and an increasing depth of general systematic analysis tools, there are still causal factors missing out. A recent study identifies language issues as an underestimated danger. Dutch Labour Inspectorate records identify procedures and communication as an important causal factor area for major accidents. Accident investigation method taxonomies that are frequently used in The Netherlands, were investigated on the content related to language issues. Language issues are found to be either present less than proportional with observed accident rates or not present at all in frequently applied accident investigation classification systems. Hence a new taxonomy problem was found in Dutch accident data. Language issues need more attention in accident investigation methods.