Is yeah a word used in proper English?

"Yeah" is considered informal English. It's widely used in everyday conversation and casual writing, but it's not generally considered appropriate for formal settings like academic papers or business correspondence.

Here's a breakdown:

* Informal: "Yeah, I'm coming."

* Formal: "Yes, I will be there."

While "yeah" isn't considered "proper" in the most formal sense, it's a perfectly acceptable word in most everyday contexts.