The quality of being informal and conversational in a way that is not considered standard in language.
Slanginesses can be fun and expressive, but it is not always appropriate in formal situations.
Examples:
The slanginesses of their speech made it hard for me to understand.
I like the slanginesses of that song's lyrics.
She doesn't like the slanginesses of his jokes.
The slanginesses of their conversation made me laugh.
The slanginesses of his writing is hard for me to understand.
The slanginesses of their speech is like a secret code.