> To open a en-US XLSX file in a fr-CA copy of Excel, you will need the en-US language pack
Are you sure? That sounds insane. Maybe if you're exporting a CSV where you insert the formulas as text, and expect the Excel to do some magic conversion..
I'm pretty sure that XLSX file is "universally" openable, and the user using the fr-CA copy of Excel will see =SOMME( ... ), doesn't matter what locale the source Excel is.
ChatGPT says:
> The Office Open XML specification, standardized as ECMA-376 and ISO/IEC 29500, defines how formulas are stored in XLSX files. It specifies that:
> Function names and formula grammar are stored in a locale-independent (invariant) format in the file — specifically, English-language function names.
> You can find this in: ECMA-376, Part 1: Fundamentals and Markup Language Reference, Section 18.17 “Formulas”