Totally agree.
Once me and my friend who was working in a store were talking when two chassidish gilrs walked in and began speaking yiddish about us. My friend is chassidish, but dresses like she’s litvish and was speaking with me in hebrew and english. They totally thought she didn’t undertsnad…
After they paid she said good night in yidish to them, but they just thought she was one of those people who knew like 5 words in another language and when meets people who actually speak the language, tries to impress them with their large (not) knowledge. So they laughed.
But when they left the store, it was us who were laughing more.