system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why did it became common to say "Two-thousand fifteen" for the year rather than the one-syllable shorter "Twenty Fifteen", as we did in the previous century ("Nineteen Fifteen")?
gpt
We got used to it between 2000 and 2009

While Twenty Fifteen is better, Twenty Oh-Nine doesn't sound right.

So for a decade we were saying 'Two Thousand and 8' 

Twenty-Ten was kind of common, but 'Twenthy Eleven' sounds kind of odd... 

Twenty-Twelve was popular, probably due to alliteration, same as Twenty-Ten. 

Before 200 of course saying 'One thousand nine hundred fifteen' or 'Nineteen hundred and fiften' would be excessive, so 'Nineteen-Fifteen' was almost always better.  

I think you will hear both Twenty Fifteen and Two Thousand Fifteen both quite commonly though. 

You'll definitely hear '2016' as Twenty-Sixteen. because it's an election year for the US, and those years become used in slogans and catchphrases etc... 2012 had a similar effect with both the election and the stupid Mayan thing.