Frog is an integration of memory-based natural language processing (NLP) modules developed for Dutch. All NLP modules are based on Timbl, the Tilburg memory-based learning software package.
The VU worked on a timbl-based semantic role labeler for Dutch. I think it would be an interesting idea to integrate this in Frog. See https://github.com/newsreader/vua-srl-nl
This is less obvious than I assumed. They base themselves on constituency and dependency information (alpino output), we don't have the former and the quality of the latter is too poor.
The VU worked on a timbl-based semantic role labeler for Dutch. I think it would be an interesting idea to integrate this in Frog. See https://github.com/newsreader/vua-srl-nl