I read a little of your story, but I’m not the best person here to be making suggestions, but anyway.
These are my opinions.

Dialogue should flow freely and unobstructed. Close to how it is in life as possible. I noticed that at times you add information as dialogue is being exchanged.

Example - 'All right, mamma.' Mustapha sat up in bed, yawning like a cat and stretching his arms as far as he could. 'Humm! Exquisite,' he said when the smell of couscous reached his nose.
'Don't forget to take the dough to the public oven,' reminded Khalti Icha. 'I want it back before midday, right?'
At this point you add an entire paragraph before Mustapha answers his mother.

As any other Algerian mother, Khalti Icha strongly hoped Mustapha would remain a child forever. He had always been a lively and lovable little boy, who never caused any problem. He was so careful not to disobey her that he would even avoid eating out of the same plate as her. She was determined the young boy must follow in the path of his deceased father, whose reputation as a wise town leader was well established, even after his death.

'All right, mamma,' replied Mustapha with a smile.

I’ve rewritten this as mostly dialogue only. I’m not suggesting you do this but to show how much more natural it sounds.'Wake up, Mustapha,' Khalti Icha called her son.

'All right, mamma. Humm! Exquisite,' he said as the smell of couscous reached his nose.
'Don't forget to take the dough to the public oven; I want it back before midday, right?'
'All right, mamma,'

The following is from a modern master at dialogue, Cormac McCarthy. From The Road.

—At the top of the hill he turned and studied the town. Darkness coming fast. Darkness and cold. He put two of the coats over the boy’s shoulders, swallowing him up parka and all.
I’m really hungry, Papa.
I know.
Will we be able to find our stuff?
Yes. I know where it is.
What if somebody finds it?
They wont find it.
I hope they dont.
They wont. Come on.
What was that?
I didnt hear anything.
Listen.
I dont hear anything.
They listened. Then in the distance he heard a dog bark. He turned and looked toward the darkening town. It’s a dog, he said.
A dog?
Yes.
Where did it come from?
I dont know.
We’re not going to kill it, are we Papa?
No. We’re not going to kill it.
He looked down at the boy. Shivering in his coats. He bent over and kissed him on his gritty brow. We wont hurt the dog, he said. I promise —

This is bare bones dialogue and writing, but it serves to show my point about dialogue flowing naturally with few obstructions.
Sometimes, as practice as much as anything else I take two or three characters and write them through a dialogue exchange without any tags and try to make each differentiable from the other by the way they talk. It is also a good way to build characters. That’s mostly what characters do in writing anyway, they talk. Let them talk and don’t interrupt by writing while they are talking. Do that at other times.
I hope this helps a little.
thank you ...

Chuck and Ros, I'm mighty grateful for your help!
I am utterly thankful to you both for at least taking out time to reply to me. ANd I found your advice very helpful and reassuring at once.

As for Chuck, I do understand what you mean exactly, however I can't help inserting actions while dialogue is being exchanged. I wonder if there's a way to do this without obstructing my characters' speech.

As for you Ros, I think you're extremely right ("he said, giggling" rather than "he giggled.") I used to do this a lot, but some reviewers picked up on it, suggesting that using "ing" form after s/he said is not suitable in modern literature.

Again, thank you very much for your advice. I have found this extremely helpful.

Greetings Erict,
Thanks for taking out time to reply to me, pal.
You've really hit the spot. This is what I think of very often. Even if i've reached the Betseller chart, but still receiving reviews like "your dialogue doesn't work for me"

That's it, kate! Besides the advice offered by Chuck, Ros and Erict, yours seems clearer and more concise. Now, I'm beginning to understand how one should construct his dialogue.
Thanks for you all