Do the rom selector trick, I have done it since switching to a JPN N3DSLL
1. Make sure the game you want to play is installed as a CIA
2. In Emunand mode, have the cursor on the cia you want to play in english
3. Open the rom selector and choose a US/EUR game, (I like to use EUR smash since that's always in my gateway SD card)
4. BEFORE THE CURSOR AUTO-MOVES TO THE 3DS CARD ICON, press A quick enough so it launches the cia your cursor is on that you want in english.
4a.(So I select Smash in the rom slector and continue pressing A so it immediately launches STEAM).
Tested personally with a Codename STEAM cia, EUR Smash Rom, on a JPN N3DSLL Emunand on Gateway