In the movie, the wolves contains human like characteristics. That means they can think like a human, but can also pass on ideas like how humans do. The first movie clearly shows this.

Assuming the logic of that is meant to be realistic, does that make it alright for the wolves to know human phrases without showing that they learned it on the same movie?
The answer is long, and in short, it's a "yes".

In Ratatouille, Remy was able to know how to cook, and know a lot of human phrases because he learned how to, and even the movie showed that.
Alpha and Omega did not do that.

But...
Many can assume many anthropomorphic animals in zoos (e.g. Madagascar?) can learn because they been around humans. One can also assume Humphrey saw a native American which cause him to know rain dancing and danced for it.
However, these are theories related to a basic form of logic a human thinking like non-human animal can do, and in one case it can be assumed without even showing it on the movie or show. And yes, that makes sense too. Usually many things are made up of things existing in some past.

And that's the thing.
Not only you can do the same logic in some sequel cases, these type of creatures has a mind like a human, and they can learn as I already said. However, having the mind like a human also means they can pass on information for several years in a similar way like a human because humans can do that as well.

Therefore, you can assume that Humphrey knew some phrase (e.g. that one (forgot name) reference from 5) from some human knowledge artwork because he could of learned it from other wolves and/or other animals passing off information. This type of assumption would be within the same logic as assuming knowledge because one lived with humans all their life. It's only a stretch, so it's still within logic.

Plus, we do not know every single event that happened with these characters between the movies and between some events within each movie. It is realistically possible they could of learned something involving humans in that too. Even the rain dance thing is very stretched and is the same length of logic from the plus part. Maybe even the passing information possibility.

Kinda a Conclusion?
Since these are just stretches within the same logic, if the logic excusing Humphrey knowing certain phrases in a sequel is wrong, then it would also be wrong for Humphrey to know how to rain dance from the FIRST movie, it would also be wrong for some characters from Madagascar to know human phrases because they lived in a zoo around humans, and it would even be wrong for Remy to do all that human stuff because he learned how to.
To say it's wrong is like saying it's wrong for them to be anthropomorphic.

Many of such knowing is the same logic coming from how the human mind works.

Humans Themselves
If we can assume a human knew a video game called Super Mario Bros. in a lost home on the same planet, we can assume the human knew that at some point in the past either from passing on information or went to a city and learned it from there.

If a human was born on a planet where such video game didn't exist, and there would be no way for the human to know about it, then the human mentioned it anyway, then that would make no sense. Just because this is a human, doesn't mean they can know everything by default either.

Same exact logic for Alpha and Omega wolves.

My Defense Is The Realistic?
Is people understanding this? XD
Well, being anthropomorphic like this means having a mind like a human, and if that's the case, it would make zero sense to say "You don't know that!" when in fact, it may actually be possible that they can.*
*It would only make sense for example to suggest that to a wolf that has a clear backstory clearly showing that the wolf did not have knowledge of that yet with no skipping between that part and recent event.

It's true, I do think we need to realize that some movies can be partly realistic but still have non-realistic things in it, and maybe Alpha and Omega isn't meant to be very realistic with anthropomorphism. But even with this, turns out what I am defending may actually be the realistic one. Huh...

______________
I need to remind myself that I am posting this in a group that's likely less rational, so I'm not expecting any open minded feedback?
I don't mind someone attempting to challenge me as long if it follows logic maybe. But I won't expect it. Also make sure it's safe and legal.