How do I translate PhET Simulations or the PhET Website?
Go here to learn more about translating.
When I use the embed code provided for a sim, why is the English version is shown?
The embed code that is provided on a sim page points to the English version of the sim, but it is easy to modify the code to point to a translated version by changing " _en" to the desired locale (example: "_es_PE", "_hu").