A better example of a dialogue having a predominantly metalingual character is this rhyming ''game'' from A Little Priest:
MRS. LOVETT: Now let's see...we've got tinker.
TODD:(Looks at it) Something pinker.
MRS. LOVETT: Tailor?
TODD:(Shakes his head) Something - paler
MRS. LOVETT: Potter?
MRS. LOVETT: Butler?
TODD: Something- subtler.
MRS. LOVETT: Locksmith?
TODD: Something-(Slumps, defeated)
The metalingual function often stems from a disruption in the communication-process. When two or more figures speak different languages, there are often many utterances with metalingual function. With different languages I mean two things. First when two figures really speak two languages and secondly is when two figures use different codes within one language such as dialects, sociolects and idiolects. Although none of this occurs in Sweeney Todd I have to mention it for the sake of completeness.