Some languages don't indicate plurals (such as Japanese), while for others the word will change depending on the quantity (such as Polish). Take a look at the official Unicode list of plural rules here.

• zero - used to indicate a 0 quantity.
• one - used to indicate a quantity of exactly 1.
• two - used to indicate a quantity of exactly 2.
• few - used to indicate a small quantity greater than 2, but this depends on the language.
• many - used to indicate a large number, but this also depends on the language.
• other - used to indicate every number that isn't covered by the above categories.
• floating - used to indicate a floating-point number (New).

A native apple solution requires the plural to be defined in the file * .stringsdict with strange NSStringFormatSpecTypeKey keys. However, in L10n-swift plurals can be defined in every supported format in the simplest form.