t is an Alias for translate, check out
I use a 'quick_translate' method in my ApplicationHelper:
def qt(method)
key = "web-app-theme.#{method.underscore}"
I18n.translate(key, :default => method)
end
Then in my views do:
%li
= link_to qt("GoodsReceipts"), goods_receipts_path
And in my locale file have: