Important characteristics of Skinner's (1957) definition a tact:
(The response to be analyzed is in bold text.)
The first item is not an example of a tact. The speaker is the young child. He did something (said "circle") and his behavior produced a reinforcing consequence (confirmation). We classify the child's behavior as verbal because its reinforcing consequence was mediated by a listener (his dad). However, his behavior was likely under the control of a verbal SD (his father's auditory stimulus "balloon") rather than any particular nonverbal SD.
The second item is an example of a tact. Again, the speaker is the young child. He did something (said "circle") and his behavior produced a reinforcing consequence (confirmation). We classify the child's behavior as verbal because its reinforcing consequence was mediated by a listener (his dad). In this case, his behavior was likely under the control of a nonverbal SD (the visual stimulus of a balloon), the defining feature of a tact.