Diglossia
In Sinhala there is distinctive diglossia, as in many languages of South Asia. The literary language and the spoken language differ from each other in many aspects. The written language is used for all forms of literary texts but also orally at formal occasions (public speeches, TV and radio news broadcasts, etc.), whereas the spoken language is used as the language of communication in everyday life (see also Sinhala slang and colloquialism). As a rule the literary language uses more Sanskrit-based words.
The most important difference between the two varieties is the lack of inflected verb forms in the spoken language.
The situation is analogous to one where Middle or even Old English would be the written language in Great Britain. The children are taught the written language at school almost like a foreign language.
Sinhala language also has diverse slang. Some is regarded as taboo and most is frowned upon as non-scholarly.
Read more about this topic: Sinhala Language