Tradução "not only could it be or might it be, it will be"

O trecho abaixo faz parte de um monólogo com o qual me deparei no youtube

"If I may say it... I think that your English really could get better, and you really will ask yourself: might it be that I could finally be improving?, would you say my English is better than it's ever been?, I would say that after a conversation(in English), not only could it be or might it be , it will be better."

Nesse finalzinho: "I would say that after a conversation, not only could it be or might it be, it will be better.

Minha dúvida é: por que ele usou o modal verb "might" que indica possibilidade, se ele já tinha usado "could" que também indica possibilidade? Pra mim ficou tipo "poderia" 2 vezes.