Can you give some more details about ‘underlying slide master’?

Here are some localisation tips, especially for quiz slides:

• Create custom Preferences for each language, and import them. The quiz preferences specifically allow you to translate the Default labels (including button labels) to the wanted language.
• Create a custom theme for each language. Depending on the language it may be necessary to increase the size of different areas on the quizzing master slides.
• Use GIFT import for quiz text. It is much easier to translate and import. In the blog posted below I explained why I prefer GIFT over CSV.

I didn’t blog recently about localisation, here is the most recent post:

CSV import – localisation – eLearning (adobe.com)