I know the review process is unpredictable at best. To avoid a discussion of opinions, I'm looking for answers from people who have submitted apps without localizations, then submitted the same app later with the only changes being the addition of localization in several languages.
If the review process is significantly longer than the original app, then the answer may be yes.
I'm curious if they need to send the app to different countries for review, as some countries will block certain types if information (China, for example).
Of course if you can post information other than this which is still relevant it would be appreciated.
If you are submitting the app during the christmas holiday season rush, review times may be more. The average per day app submission in this time is lot higher due to Apple shutdown during holidays, and developers trying to get their app just in time before shutdown.
That said, here's my observation for non-holiday seasons submission. We have an app that has been localized for 24 locales, including China. I never experienced any specific pattern in changes in review times before localization was put (was english only at one time, later all the localizations were added) vs after localizations were added. I had one time an update that went live within 48 hours of submission with around 19 localizations (including chinese, finnish, russian etc in it) in it. On the other hand, once a Finnish only app that I submitted took almost 2 weeks. Most of my apps are utility or education.
I think its more to do with type of app + rating (if its got some controversial material in it) + when you submit it (christmas holiday season or not).