Here is my exam procedure. Students have been working together with a partner for the previous 3-4 weeks.

There is a list of the order in which pairs will do the dictation. WHEN it is their turn, I call each pair over to sit at two tables turned to face each other. In between the 2 tables, there is a screen which prevents the students seeing the other's card.

I try to put student A consistently on either the left-hand side, or the right-hand side, so that I can follow the dialogue. I sit at another table, facing the 2 students. My table makes a triangle with their tables. I have a copy of the dialogues they are doing to help me follow along. Typically, the dialog is in 3 separate sections and there are 2 parallel texts for each section. The students have practiced the same or similar texts in the previous weeks.

1. I give each student their card, and get them to sign it. When

they have signed it, they can turn it over to look at the 
dialogue.

2. I say, 'No Chinese.' I say, 'You're A. You're B. Are you

ready? Go.'

3. I then start the stop watch. They have 3 minutes.

4. I don't think I have to tell them what they have to do, but if

they have absolutely no understanding, I say to A (or B), 
'Read this line,' and I point to the line in the dialogue that 
they have reached. If they still don't read, I spell the 
individual letters of the words for the student, and have them 
repeat the letters.

5. If they use Chinese, I look sternly at them, and repeat, 'No

Chinese,' and I keep a tally of the number of times they use 
Chinese on the schedule, next to their names. In particular, I 
don't allow them to discuss problems they have doing the 
activity and to ask each other questions about what they are 
supposed to do in Chinese. One of my aims is to get the 
students to practice clarification requests, and comprehension 
checks in English. In other words, I want them to learn how to 
repair misunderstandings, by experiencing those 
misunderstandings. If they do this in Chinese, this is a 
significant degradation of the value of the activity, I think.

6. Looking at their partner's card or showing their card, or

pointing at it, or open book is not okay.

7. Calling the apostrophe, 'ipiei,' or 'dotien,' is not okay.

That's Chinese. Calling it a comma is okay. 

8. Sometimes, students will not read the dialogue to each other,

but will just try to fill in the missing letters. I want the 
exam to be a listening and speaking exam, so this is not okay. 
I say to the student, whose turn it is, 'Read the line,' and 
point to the line they have reached. Of course, it is okay to 
hesitate, and to think, and to fill in missing letters while 
they wait for their partner to speak.

9. Anything else is okay. In particular, using gestures, broken

English, and tapping on the screen to get their partner's 
attention is okay. In addition, instead of reading the 
dialogue, just spelling the individual words in turn is okay.

10. Quite often, I forget to start the watch. I only realize

after 1-2 minutes. I usually just start the watch, and let 
them run on to the end, and make a note in the comments, 
about starting the watch late.

11. After 3 minutes, I take the cards from them. I show them each

other's cards. This is important feedback.

The students have done this before in week 4, so if you are uncertain about any aspect of this procedure, they may be able to help.