Mormon’s efforts to save his people both physically and spiritually have failed, but he still has a mission to perform, and he closes out his record by focusing on that purpose.
The phrase “speak somewhat” in the Book of Mormon appears, without exception, in connection with a first-person narrative. Sometimes it begins a new section, at other times, it is used to transition from description to explanation. This is not just Mormon the editor engaged in redaction, but Mormon the author speaking for himself. What follows is Mormon’s intended conclusion.