Launch parameter for changing culture no longer working with additional launch parameters. Also tested on packaged 4.19 project with same result.
1. Print GetCurrentCulture (or GetCurrentLanguage or GetCurrentLocale) on tick
2. Add -culture=es to Additonal Launch Parameters in Editor Preferences -> Play -> Play in Standalone Game (Advanced Dropdown)
3. Play in Standalone game
Observe in 4.17 culture will change, in 4.18 and 4.19 it will not.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-58833 in the post.