eToys uses a custom gettext implementation for it's internationalization / localization (i18n/L10n).
Unfortunately this custom implementation does not currently include gettext plural handling. This is a shortcoming. English (and therefore eToys PO files) has two plural forms used and the plural is used when the number is not equal to 1 [nplurals=2; plural=(n != 1)] in Poolte-speak; however, many language have different plural utilization.
gettext pluralization is capable of handling this complexity and offering localizers the opportunity to input the correct pluralization in a single string (with multiple plural form entries). This produces a more grammatically correct user interface. Being grammatically correct is important in the educational setting.