dikti

This is the verb underneath diktatoro, and it is perfectly innocent. The word page for the dictator fences off the person and the regime; this is the daily job the root does the rest of the time. Dikti leteron is to dictate a letter, dikti al la klaso is what a teacher does at the start of a language lesson, and there is nothing sinister in either. Only the derived nouns went political: diktatoro is the man, diktaturo the system, diktatora the adjective. The bare verb stayed with the secretary and the notebook.

Two senses, and the second one is figurative in the same way English is. Literally, you speak words for somebody else to write down. Figuratively, you impose a decision on somebody who does not get a say: dikti kondiĉojn, to dictate terms, or ne diktu al mi, do not dictate to me. Esperanto did not invent this stretch, it inherited it from every source language at once, so it reads naturally to everybody.

The family worth knowing. Diktaĵo is the thing dictated - a dictation exercise, the passage itself - built with -aĵ-, the suffix for a concrete product of an action, so it stands in the same relation to dikti as manĝaĵo does to manĝi. Diktilo is a dictaphone, on the tool suffix. Diktado is the activity, the practice of dictating, and if you want the person you say diktanto. Every one of them decodes without a dictionary, which is the whole argument for learning the affixes before the vocabulary.