The Language can be changed in both applications by clicking the ‘languages’ icon (represented by a globe), located at the bottom of the screen in Merge Explorer and at the bottom of the left-sidebar in Object Viewer.
From there you can choose from our list of languages. Give the application time to update to the chosen language onto the app. Languages available are: English (US), English (UK), Spanish, French, Germain, Hindi, Chinese (Simplified), Chinese (Traditional), Japanese, Italian, Russian, Dutch and Portuguese!