.language String method does not work on Ruby 2.4.0

[jm3]

Instead Whatlanguage throws undefined method `language' for "foo":String:

NoMethodError: undefined method `language' for "Deux autres personnes ont été arrêtées durant la nuit":String
from (irb):26:in `block in irb_binding'
from (irb):26:in `each'
from (irb):26
from ~/.rvm/rubies/ruby-2.4.0/bin/irb:11:in `<top (required)>'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli/exec.rb:75:in `load'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli/exec.rb:75:in `kernel_load'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli/exec.rb:28:in `run'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli.rb:424:in `exec'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/vendor/thor/lib/thor/command.rb:27:in `run'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/vendor/thor/lib/thor/invocation.rb:126:in `invoke_command'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/vendor/thor/lib/thor.rb:387:in `dispatch'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli.rb:27:in `dispatch'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/vendor/thor/lib/thor/base.rb:466:in `start'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/cli.rb:18:in `start'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/exe/bundle:30:in `block in <top (required)>'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/lib/bundler/friendly_errors.rb:122:in `with_friendly_errors'
from ~/.rvm/gems/ruby-2.4.0/gems/bundler/exe/bundle:22:in `<top (required)>'
from /usr/local/bin/bundle:22:in `load'
from /usr/local/bin/bundle:22:in `<main>'
from ~/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `eval'
from ~/.rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `<main>'

[yun-cn]

require 'whatlanguage/string'