그러니까 is very commonly used in conversations and is used in several different ways. It’s not only used to mean ‘because is so’ and is also used for various interactive motivations.

This video attempts to explain the various use of 그러니까 by analysing dialogues in which it occurs. The five main usages are as follows:

i) Causal connective
ii) Stating agreement
iii) Repair own dialogue
iv) Repair other’s dialogue
v) Reshaping set domains