However Brave couldn't guess that I meant Reckless Kelly when I asked it;
What is the Australian movie with a dog who can say cornflakes?
When I gave it more details;
What is the movie starring Yahoo Serious and featuring a dog who can say cornflakes?
.. it correctly guessed Reckless Kelly, but flat-out denied that the dog says "cornflakes". It's the only word it can say and it's hilarious when it says it.

Search query: "What is the movie starring Yahoo Serious and featuring a dog who can say cornflakes?"
Quick Answer: The movie you are referring to is Reckless Kelly.
References:
- Yahoo Serious made 3 movies, seemingly disappeared off the ... - Reddit
- Reckless Kelly - Corn Flakes - Part 1 - YouTube

Search query: "What is the Australian movie with a dog who can say cornflakes?"
Quick Answer: The Australian movie with a dog who can say "cornflakes" is Reckless Kelly. This 1993 film, directed by Yahoo Serious, features a talking dog that only says "cornflakes."
References:
- Reckless Kelly - Corn Flakes - Part 1 - YouTube
- Reckless Kelly - Corn Flakes - Part 2 - YouTube