Well, LA has some internal features for subtitle stream selection, depends on enabled options.
For example, you can take a look to Preferences->OSD->Subtitles, and there you can see option named like "subtitle language by default" (sadly, but its broken in 4.9.0, will be fixed in 4.9.1, but working in 188.8.131.52).
Also, you can enable two
subtitles in the same time (just right-mouse-click on "Subtitles" button at Control Panel).
Let me know if you satisfied with answer. And if you not, then we will figure out something for you.