The French spelling reform: plural forms
An additional area dealt with by the French spelling reform involves the plural forms of various words where current usage is either inconsistent or uncertain. The principle idea of the reform is that the plural of loanwords and French compounds is regularised.
Plurals of loanwords
As in English, there is sometimes hesitation in the formation of the plural of loanwords in particular as to whether to adopt the plural form of the original source language or to "gallicise" the plural (in other words, make it sound identical to the singular and write it with a final -s). The situation is similar to English where speakers hesitate, for example, about whether to pluralise syllabus as syllabuses or syllabi. And as in English, this confusion extends to "learned" loans from Latin, such as maximum (for which plurals maximums and maxima exist).
The reformed spelling aims to do away with such hesitation: loanwords are always pluralised with -s, even if that strays from the "original" plural form of the source language.
As with French words, those ending in -s, -x, -z remain unmodified in the plural.
Thus, the reform favours plural forms such as:
Plurals of compounds
There is currently some variation in the use of the plural -s on the end of compound words such as ouvre-boîte(s). In this case, for example, the final -s is essentially optional in either singular or plural, and adding the -s does not necessarily distinguish singular "bottle opener" from plural "bottle openers". In a case such as porte-bagages, the usual spelling was to adopt the plural form in all cases, as the word bagages upon which it is based is generally used in the plural. In other cases, dictionaries advocate that a particular word is invariable, seemingly arbitrarily.
The reformed spelling simplifies this situation: in the singular, such compounds are written without the -s, and in the plural, -s is used as a plural marker: