Extremely easy way to detect language of text using google translate:

require "rubygems"
require "net/http"
require "open-uri"
require "cgi"
require "json"

def detect_language(content)
	base_url = 'http://www.google.com/uds/GlangDetect?v=1.0&q='
	url = base_url + CGI.escape(content)
	response = Net::HTTP.get_response(URI.parse(url))
	result = JSON.parse(response.body)
	return result['responseData']['language']
end

if detect_language("To powinnien być polski!") == "pl"
	puts "Witam"
elsif detect_language("This should be english!") == "en"
	puts "Hello!"
end