What does a filthy mouth will not utter decent language mean?

The phrase "a filthy mouth will not utter decent language" means that someone who habitually uses vulgar or offensive language is unlikely to be able to speak politely or respectfully.

Here's a breakdown:

* Filthy mouth: This refers to someone who regularly uses curse words, slang, or other offensive language.

* Decent language: This refers to polite, respectful, and appropriate language.

The phrase suggests a strong correlation between the type of language someone uses and their overall communication style. It implies that someone who constantly uses foul language has difficulty expressing themselves in a more refined or appropriate manner.

It's important to note that this is a generalization, and not everyone who uses strong language is incapable of using decent language. However, the phrase highlights a common observation about the relationship between language habits and communication style.