Google translate with offline speech input?

Anyone know how to get Google Translate working with offline speech input (e.g. in airplane mode) on the Idol 3? This worked for me on my old Moto phone running KK (actually, running CM11). But on the Idol 3, I can do offline translation via typing (having downloaded the relevant offline language packs), and I can get the app to speak either the typewritten input or output, but when I tap the microphone to activate speech input, I get a never-ending "initializing" message. Voice typing itself works offline (e.g. I can compose a notepad note), just not within Google Translate.