The German word Kindergarten has become part of the English language in the form of kindergarten. Interestingly, many native and non-native speakers instead use kindergarden. However, the dictionaries I consulted only include the word kindergarten. Moreover, there is no official support for pronouncing kindergarten like kindergarden. The Oxford Learner’s Dictionary provides the British and the American pronunciation here. In both cases, –garten is pronounced with a t rather than with a d. You can compare the pronunciation to that of garden by following this link.
While the incorrect spelling kindergarden is quite easy to spot (the WordPress spell checker is telling me right now that something is wrong), the pronunciation is more tricky. Have a look at the trailer of Kindergarten Cop,
and compare it to the Oxford English pronunciation. It’s hard to decide whether they say kindergarten or kindergarden in the trailer.