I installed all language packs for Excel 2016, monthly targeted, by using the Office Deployment tool. I noticed, that for some languages, the new forecast functions have only be partially translated. Three languages affected are shown in the screenshot below.
When a user is e.g. starting to type a function name in an Excel cell, a list of functions appears. If a user of one of the affected languages starts typing e.g. FORE, then the translated forecast function does not appear in the list. For example, if someone is using Excel in Maori, the translated forecast function appears in the list only when start typing M.
As the forecast functions are meaningfully grouped by the prefix FORECAST, I personally think, it would better to then translate all forecast functions or keep the currently translated one(s) in English.
For Catalan, we have the inverse case: all of the new forecast functions are translated except one. In this case, I would like to suggest to translate the remaining one.