I can't imagine why anyone would ever want to share an entire speech bubble, without any context (as in a screenshot).
On the other hand, it's obvious that given a message like "My address is 123 Xyzzy Rd, come anytime," the user would only want to select a subset, not the entire message.
On the other hand, it's obvious that given a message like "My address is 123 Xyzzy Rd, come anytime," the user would only want to select a subset, not the entire message.