最後まで言わせてって英語でなんて言うの？

In US culture, interruptions during conversation are quite common, although they can certainly be irritating! There are two ways to deal with them.
One, you can interrupt in return!
To do this, phrases like, "Wait, wait, let me finish," or "Hold on, I'm not done," are very appropriate.
But if you feel uncomfortable interrupting, you can also wait until the other person finishes and then say, "
Can I finish what I was saying?" You can add, "before" or "earlier" at the end as well, like so: "Can I finish what I was saying before?"

Have a wonderful day!

"I wasn't done speaking. Can I continue?" is a polite and informal way of letting the teacher know they interrupted you, and you'd like to finish your statement.

example:
You: "I wasn't done speaking. Can I continue?"
Teacher: "Oh of course!"

"Excuse me, may I finish what I was saying?" is a more formal way to ask the teacher if you can continue and letting them know that they have interrupted you.

example:
You: "Excuse me, may I finish what I was saying?"
Teacher: "I apologize for interrupting you. Go ahead."

"I think you interrupted me. Can I finish?" Is a very direct way of letting the teacher know the situation at hand.

example:
You: "I think you interrupted me. Can I finish?"
Teacher: "Yes, of course! I'm so sorry for the interruption."

Simple ways of stopping the interruption and continuing.

'Please can you let me finish.' asks politely to let you finish what you were saying.

1. You may not actually feel sorry, but this is a polite way to express to the teacher that you were interrupted. Sometimes, in their enthusiasm, teachers may feel the impulse to impress a point, not meaning to interrupt however!
2. Here you ask for permission to continue what you were saying when you were interrupted.

You can say "can I continue?" or "You interrupted me. Let me finish please."
---------------------------------
A : Can I continue?
B : Yes, sure.
---------------------------------
C : You interrupted me. Let me finish please.
D : I'm sorry.

Sometimes, interruptions occur accidentally and someone may not even know they have done it, therefore this situation should always be handled with politeness.
'Sorry, I wasn't finished. Can I continue?' is a very common way to let someone know they interrupted you without you literally saying so. And, to be apologetic (even though you may not actually be sorry) is very common in these situations.

When trying to relay that someone may have interrupted you it is important to remain polite. In the efforts to relay a message such as this cordially you may use phrases such as 'I'm sorry' and 'excuse me' so that you avoid offending anyone.