Dianne Wiest said she really struggled with Helen Sinclair's signature line.
She finally decided to lower her voice when she said "Don't speak!" The lower she said it, the funnier it became.

Cheech's last line, "Don't speak!", was ad-libbed.

David's first line of the film is "I'm an artist!"
His last line of the film, with the exception of his proposal to Ellen, is "I'm not an artist."