Answer:
It creates an informal and familiar tone.
Explanation:
When we refer to the concept of "register" we talk about how a speaker/writer addresses the listener/reader. This can be done in 4 different ways: Informal, familiar, formal, and ceremonial.
An Informal register is identified when there is a link between the participants of the communication, they exchange information in a casual way, and colloquial language is used. However, grammar is preserved.
A familiar register implies that each participant really knows the other person and communicate in a very relaxed way. It can be seen in the way they use informal language such as slang and not caring too much for grammar, for example.
A formal register implies the use of language which is not personal, avoiding the use of slang. Grammar is respected and it has an objective approach, that is to say, language is objective.
A ceremonial register is the less common of all and it can be usually found in old documents. Some of the vocabulary present in these documents can be totally new, and that is why it can be confusing, making the reader/listener think of it as formal.
