Hi ChristianKl and thank you for your question!
Currently Wikidata doesn't work as a dictionary (even though there are plans/considerations to integrate Wiktionary there). However, our hope is that the lexicon for Wikispeech and recorded pronunciations for words would be valuable to add either to Wikidata or Wiktionary in the future. See #7 here. One way could be to upload files with the sound recordings onto Wikimedia Commons, with the IPA as part of the metadata, another option is to connect different words to the Wikispeech database. This is something we have to look into a bit more.
Cheers