"Whyncha" is a colloquial or informal expression used in some regions, especially in areas with strong Scottish or Irish influences. The abbreviation of "Why not"
"Whyncha" Examples
Whyncha
Emotion marker, often used to soften the tone of a question, similar to "don't you think".
1. "This cake is delicious, whyncha give me a slice?" 2. "I had a nice day out, whyncha come join me?" 3. "You should go out tonight, whyncha?" 4. "Whyncha try the new restaurant downtown?" 5. "You're always up early, whyncha teach me how to get up so early?"