We were expecting 30 people to come, but half of them never showed up.

[it-is-niaz]

1. We were expecting 30 people to come, but half of them never showed up.
2. We expected 30 people to come, but half of them never showed up.

What is the difference between them?

 

[Yankee]

No difference in meaning as presented. But in number (1) the listener/reader would expect a result as presented. In (2) a result might or might not be necessary depending on context.

 

[jutfrank]

The first sentence is better. The continuous aspect works nicely to set the expectation as progressing over time.

 

[Raymott]

Half of them "didn't show up". The use of 'never did', at least in Australia, is generally substandard when it means "did not".

Kids at school:
A: "You stole my lunch money!"
B: "I never did!" (Used to mean "I did not!") This is a poor prognostic sign for developing good communication skills.

 

[jutfrank]

Half of them "didn't show up". The use of 'never did', at least in Australia, is generally substandard when it means "did not".

Agreed, and not just in Australia. In schools in some parts of the UK, you might hear a dialogue like this:

A: Miss! Ollie kicked me.
B: No, I never.

Obviously meaning No, I didn't. There's no need in the OP sentence to use never.

 

[tzfujimino]

There's no need in the OP sentence to use never.

In that case, the sentence sounds better to me with the addition of "only":
We were expecting 30 people to come, but only half of them showed up.

Am I wrong?

 

[GoesStation]

In that case, the sentence sounds better to me with the addition of "only":
We were expecting 30 people to come, but only half of them showed up.

Am I wrong?

No, that's a good sentence.

 

[jutfrank]

In that case, the sentence sounds better to me with the addition of "only":
We were expecting 30 people to come, but only half of them showed up.

Am I wrong?

only half of them showed up
half of them didn't show up

I don't think one is better than the other since they focus on different things.

 

[tzfujimino]

Do "half of them showed up" and "half of them never showed up" mean the same thing? (I understand the number of people who showed up and (the number of people) who didn't is (are?) the same. I'm asking about the difference in nuance they convey.)

 

[jutfrank]

Do "half of them showed up" and "half of them never showed up" mean the same thing? (I understand the number of people who showed up and (the number of people) who didn't is (are?) the same. I'm asking about the difference in nuance they convey.)

I wouldn't say there's a difference of meaning, but a difference of use. If you're talking about meaning, a half is a half. There's no nuance in that. Also, it's very unlikely that the speaker is being exact about these proportions, anyway. It's either an approximation or an exaggeration.

The difference is the focus. Which group do you want to focus on? The people that showed up or the people that didn't?