Text speak is a device used mostly by young people who think it's 'kewl' and older people who should know better. In essence it's just like English but without any vowels (e.g. not text but txt). Numbers are also used to represent sounds as in 'gr8' instead of great, '2' instead of to etc. With the availability of the predictive text facility on modern mobile telephones it should be dying out but it appears not to be.
Basically ... 2days yoof r lzy cnts.
Thankfully people who post on Arrse using text speak are usually hounded mercilessly by the other site members until they desist, or stop posting altogether until their mental wounds have healed.