def irregular(singular, plural)
@uncountables.delete(singular)
@uncountables.delete(plural)
s0 = singular[0].chr
srest = singular[1..-1]
p0 = plural[0].chr
prest = plural[1..-1]
if s0.upcase == p0.upcase
plural(/(#{s0})#{srest}$/i, '\1' + prest)
plural(/(#{p0})#{prest}$/i, '\1' + prest)
singular(/(#{s0})#{srest}$/i, '\1' + srest)
singular(/(#{p0})#{prest}$/i, '\1' + srest)
else
plural(/#{s0.upcase}(?i)#{srest}$/, p0.upcase + prest)
plural(/#{s0.downcase}(?i)#{srest}$/, p0.downcase + prest)
plural(/#{p0.upcase}(?i)#{prest}$/, p0.upcase + prest)
plural(/#{p0.downcase}(?i)#{prest}$/, p0.downcase + prest)
singular(/#{s0.upcase}(?i)#{srest}$/, s0.upcase + srest)
singular(/#{s0.downcase}(?i)#{srest}$/, s0.downcase + srest)
singular(/#{p0.upcase}(?i)#{prest}$/, s0.upcase + srest)
singular(/#{p0.downcase}(?i)#{prest}$/, s0.downcase + srest)
end
end