I think asPlural adds a stumbling block on the way to a fully localized squeak. The only use of asPlural by now is in Object errorNotIndexable:
self error: self class name asPlural , ' are not indexable'
This can be easily rewritten as:
self error: ('Instances of class {1} are not indexable' translated format: self class name)
This might not look as slick as before but circumvents creating the plural form of a word and it is translatable. If asPlural stays in the image and gets more used beside the context of the programming environment, there will be a need for language specific versions of that method. And they might be not as easy to write as the current one.
I'm by no means an expert on that topic, but I feel we should leave out methods that generate language in favour of an easier to translate squeak image.
Just my 2 eurocents, Alex