What's the plural form of Vietnamisation? Here's the word you're looking for.
Answer
The noun Vietnamisation can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be Vietnamisation.
However, in more specific contexts, the plural form can also be Vietnamisations e.g. in reference to various types of Vietnamisations
or a collection of Vietnamisations.