Hmm, ARPA mobile performance on my end is usually fast. My test language model of approximately 400 words returns responses for long sentence dictation on an iPhone 4 in about 1-4 seconds, which is fast considering how constrained the CPU and RAM are on the device versus any desktop.
All the audio and processing code is in C whether written by me or as part of one of the dependencies. I’m pretty sure after a year and a half that there is nothing “wrong” per se with the framework performance, but it could be that you are encountering an issue with your application.
I would say that I’d need some timing examples with information about the following items:
ARPA or JSGF?
Is the acoustic model 8-bit or 16-bit?
What is the size of the language model or grammar?
How far away from the phone are you when speaking? (this has a huge effect for dictation applications)
What are you trying to recognize? Words, sentences, phrases?
Please show some representative time results along with the device they are taken from (not simulator). Feel free to show logs that have both OPENEARSLOGGING and VERBOSEPOCKETSPHINX turned on so it is possible to see the exact processing times once complete speech has been detected until the hypothesis is returned. I remember that the last time there was a similar question about ARPA, it turned out that something in the app was blocking recognition (although JSGF performance is unfortunately poor on the device, so if it is actually a JSGF grammar, that will be slow).
My other question is whether you have tested similar size models in English on a device, so you can rule out that it is connected to your acoustic or language models.
I don’t really think device vs. desktop is a fruitful discussion, since it is the expected result to see really dramatic performance differences there (or all the other implementations of speech recognition for the iPhone would not be server-based). But I’d be interested to know what kind of device performance you are seeing and also how it compares to similar-sized models in English, in case there is something specific to the Turkish model or implementation that is slowing things down.