The site boldly claims 'All the words in the world. Pronounced.'
Whilst this may be an exaggeration, there are (at time of writing) 950,802 words, 991,178 pronunciations in 268 languages on the site.
If you want to know the pronunciation of a word in a certain language, you can search the site by language and topic and, if it doesn't appear, request a pronunciation.
The (free) site works by relying on its members to give as well as take, offering their linguistic skills to help others. Whilst there is no obligation, it seems to work well. An example of crowd sourcing and cooperation that could perhaps be a model for future educational support materials?