When you have opted for a very targeted localized approach, one that addresses even region-specific language versions, you have decided to go all in; the path is hard but the road to success is certain. No matter what the number of locales or language versions, the investment does not have to be double.
At Commit we have implemented the process of language adaptation where we can localize in one target language and then adapt the localized outcome for use in a different locale. One typical example is with Spanish for Spain and Spanish for Latin America, or with French for France and French for Canada or Belgium.
Language versions differ when used by different cultures in different settings; not everything is potayto, potahto!