1. Low Fall tone in commands sounds very powerful, intense, serious and strong. The speaker takes it for granted that he will be obeyed, e.g.:
Try the other key.
Come and have dinner with Tom.
2. High Fall tone suggests a course of action; the speaker doesn't worry whether he will be obeyed or not, e.g.:
Put some more milk in it.
3. Short commands pronounced with the Low Fall sound unemotional, calm, controlled, often cold, e.g.:
Take it. Stop it.
Intonation in disjunctive questions (tags)
Disjunctive questions consist of 2 parts. The first one is a statement and is usually said with the Falling Tone. The second part can be of 2 types:
1. Falling Tone is used when the speaker expects agreement and doesn’t ask for confirmation, e.g.:
You know him, don’t you?
You weren’t there, were you?
Lovely weather today, isn’t it?
He’s a nice fellow, isn’t he?
(I think he’s a nice fellow.)
2. Rising Tone is used when the speaker is not sure if the information is correct and is asking the listener to check it, e.g.:
They weren’t speaking German, were they?
Before a tag, there’s usually a short pause.