Elision often occurs in spoken English to speak more quickly and naturally. We'll often say 'goin'' instead of 'going' in conversation.
Pro Tip 2/3
Informal Writing
Elision is used in informal writing, like text messages, to mimic spoken language. In texts, 'cause' is an elision of 'because'.
Pro Tip 3/3
Accent Variation
Different accents and dialects have unique elisions, changing how words are pronounced. Cockney English often uses elision, such as 'fink' for 'think'.