SMS language (also known as chatspeak, txt, txtspk, txtk, texting language or txt talk) is the English language slang use in mobile phone SMS. It is an abbreviated form of English similar to a rebus. With predictive text input increasingly being used, it is becoming less common. This type of language has been alleged[who?] to not obey or follow standard English grammar; furthermore, the words used in the writing system can't be found in standard dictionaries. The invention of mobile phone messages may be considered as its source, although elliptical styles of writing dating back to at least the days of telegraphese. There are no standard rules for writing SMS languages. a lot of words can also be shortened, such as text, then turns into txt. words can also be combined with letters to make them shorter, such as, later turns into l8er. SMS is similar to AOL speak and Telex speak, and has evolved from the shorthand use in Internet chatrooms to accommodate the small number of characters allowed (early SMS permitted only 160 characters and some carriers charge messages by the number of characters sent), and as a convenient language for the small keyboards on mobile phones. Without practice, sending SMS messages can be time consuming.