The use of Extensible Markup Language (XML) for the annotation of Spoken Language Resources (SLR) is becoming increasingly common these days. Therefore the Speech Processing EXpertise centre (SPEX), which is the SLR validation centre of the European Language Resources Association (ELRA), is also being confronted more with XML. The project "Lexica and Corpora for Speech-to- Speech Translation Components" (LC-STAR) is a project that uses XML for the encoding of its resources. For SPEX, XML-based annotations are still relatively new data formats, which is why at SPEX XML-based quality evaluation (validation) technologies and procedures are being explored. This is done using the XML encoded phonetic lexica developed in the LC-STAR project as a test bed.