Students usually do not like this exercise. It is tough no doubt. But when I explain them that this is necessary then they agree to do so. Sometimes, they ask for it, like students of SASLI 2015.
The point of doing this is they may need to know a word from their friends, they may not always find a blackboard, any board or a piece of paper. What happens if they talk to someone in phone and another person tries to use a word which they probably know but cannot hear it clearly ? We can think of thousand situation like this.
To me, it helps a lot immensely, specially if I get the same students in 2nd. Year Bangla.
But, the exercise is draining and in the beginning it needs a lot of patience to learn.
I started with words with all vowel signs , this was a bit hard for them. It is best to to deal with one sign, like লে ।
These two sounds one after another is very difficult to hear in the beginning. Go slow.
Then you can spel out one word and students can write it.
ব-এ- আ-কার, ব-এ- আ-কার = বাবা
I do not use any random word. I use the words from the list of words which I use for vowel signs. Then I sue the words from ' Script and Sound' chapter of workbook of 'Epar Bangla Opar Bangla'. We have to use the high frequency words and we have to recycle them.