I am trying to organise my French language hints and tips

Numbers applies a single, language setting to the entire spreadsheet, and any new sheets that you add within it. Thus, there is no means to have a French column and English column adjacent to one another (with language rules) in the same spreadsheet. Numbers sorts columns by ascending/descending alpha, and there is no sort granularity by leading letter unless the same result is accidentally achieved by the built-in sort.

You could create two Numbers documents, one for french, and the other for english, and copy/paste the respective language columns adjacent to one another in Pages. That would be work, and as there is no linking or embedding as in Microsoft, or LibreOffice applications, updates would be une pagaille.

Here is a Pages table where the columns from the respective language-specific Numbers documents have been copy/pasted:

For what its worth, here is Apple's article, Format a spreadsheet for another language in Numbers on Mac.

Je vous en prie.