What is the term for words like “Look” and “Listen” followed by a comma at the start of a sentence?

What is the technical term for the part of speech in bold?

Look, I'm not sure what you've been told, but carrots don't glow in the dark unless they mean business.

or

Listen, the only thing keeping him alive right now is that carrot.

I want to find some information on this kind of word for a class I am teaching. I want to find more examples and instances of usage.

The problem is that I'm finding it impossible to come up with a search term that correctly encompasses it. I'm sure if I knew the technical word I could find more information myself, but just searching with "look" and "listen" is hopeless, because they are such common words.

From what I have been able to ascertain so far, the answer appears to fall somwehere between the camps of interjection and discourse marker, but not into either exclusively or perfectly.

Anything to point me in the right direction would be appreciated.

EDIT: Just to be clear, I need to know the technical term so that I can search effectively for explanations and usage examples. I will then use these to craft an explanation that is easy for the students to understand. I am not looking to use the technical vocabulary to explain things directly to students.

SOLUTION(?)

Not sure enough to post it as an answer, but it may help others with a similar problem to know that term attention-getting device seems to be used a fair amount. Here are some interesting (though slightly tangential) resources I found:

• Imperatives of visual versus auditory perception as pragmatic markers in English and Dutch
• Links between Eyebrow Movements and Voice Variations : an Experimental Investigation
• Discourse Markers in Native And Non-native English Discourse

Also found some good information here which helped me form my teaching plan, though again not precisely what I was looking for:

• As I Was Saying: How and Why to Teach Discourse Markers

Solution 1:

These words (Look, Listen) are imperatives used as interjections. You can replace them with Hey! or Gosh! or Cowabunga, Buffalo Bob!, or other exclamations, and the effect is essentially the same: Pay attention to what I'm saying!

[EDITED]: Using the term discourse marker is probably pointless because it's quite technical and doesn't help people understand why Look and Listen are used or how they function in those sentences. It also doesn't help EFL students speak better English. Terms like imperative, interjection, and exclamation are standard fare in their secondary school and university English classes and textbooks. I think that they don't need more than those to talk about these words and their function. The point, IMHO, is to teach them how to use the language, not to teach them how to talk about it, unless, of course, you're teaching a linguistics course. But in that case, I think you'd be a professional linguist yourself and wouldn't need to ask this question.

My experience in EFL classes in Japan (10 years) and Taiwan (17 years) has been that students want to learn "useful" English (whatever they think that means) and because they're taught English grammar rules from primary school on, they ask for technical grammatical information: they seem to believe that knowing the terms and the rules will help them, but this is patently false, as anyone who's lived and worked in both those countries knows.

Solution 2:

They are both discourse markers. There are almost no specific articles about their use as discourse markers in English, but they are listed often in more generic works on discourse markers. Their function as discourse markers is usually identified as "attention getters". One of the few articles written about "look", is: 'From matrix clause to pragmatic marker - The history of look-forms', by Laurel J. Brinton in Journal of Historical Pragmatics 2:2. 2001. (pp. 177–199). Another function "look" can have, is to introduce reported speech. There is an article by Susan Blackwell (I don't remember the title, but you can find it in Google Books) who identifies this function.