Switching and repeating languages equally in an experiment

Dear All,

I am trying to create an experiment in Matlab which is the following.

I have two languages L1 and L2 (lets say L1 is English and L2 is French).

The experiment is to show for instance a word in English afterwards another word in English after that a word in French after that again in English etc. So what is happening for a bilinguist the experiment should show how fast you can switch from one language to another.

Now I need to create a code in Matlab to count how many times I am switching or repeating the specific languages and at the end the number of repeating and switching from one language to another should be equal. E.g --> the first one should always be like a constant L1 L1r L2s L2r L1s L1r L2s L2r L1s. What you can see here is L1r=2times L1s=2times L2r=2times and L2s=2times. The way we are switching and repeating the languages should be equal. Now i need to create an algorithm for that in Matlab. If you have any ideas how i can proceed please let me know.

It might be super simple but i only need the initializer for this.

Thank you for your help in advance.

Looking forward to hearing from you.