Aside from distribution, marketing and screen availability (national/city quotas for Hollywood movies) in some countries, until digital distribution started to roll out in North America, EU, Japan and other countries the biggest limiting factor was the physical film itself. As in the movie was actually distributed on physical film and local overseas distributors did not want to pay for extra copies to be printed, when waiting for a few months (and reducing their own costs of showing the movie), they could obtain the used prints from North America.
While a movie would premiere on 1,000-1,500 screens in the US/Canada on its opening weekend, until some of those screens stopped showing and internal US/Canada distribution was done with most of those physical copies of the movie, the movie could not be distributed overseas for a reduced cost, which incidentally increased the studio's profit.
Here's one example that illustrates one of many possible reasons.
I know someone who works at a European DVD/Blu-ray mastering house. Recently they released an anime Blu-ray. He told me that the publisher in Japan refused to let them release any discs until all of the Blu-rays were out in Japan (where they were released one at a time).
Why?
Because the Japanese Blu-rays were much more expensive than those in the West; Japanese fans could buy the overseas discs in their place if they came out at the same time. Since the Blu-rays contained the original audio track, said fans would have lost nothing by "bootlegging".
Getting distribution is hard because screens for english titles are more limited abroad. You need to prove out the title before foreign theaters will pick it up. Obviously this doesn't apply to blockbusters which now often have global release dates.
Not a filmmaker, but I imagine the same reason why a lot of software comes out in English first, and localized versions later. It's a lot of work to localize, the work is often outsourced, and for design-heavy things the amount of internal changes even during late-stages of a project can be really high - too high to be worth involving the localizers at that point.
So you wait until everything is done and out the door before bringing in localization to actually do their thing.
