Is there some closely related language which we can fallback to? A language fallback means that translations in the other language are used when no translation in sh is available, before recurring to English (which is usually the least known language for local speakers). Some study found that sh is 94 % intelligible for sl speakers, for instance, and sl has many more translations.
Slovene would be a bad choice. In my opinion, it'd be best to fallback to Bosnian, Serbian (Latin) and ultimately Croatian before recurring to English, and the data seems to back me up. :-)
I thought hr before sr: messages are identical in 11.5 % and 10 % of cases respectively. I guess either may make sense.
I completely agree with Srdjan m. Just to add up, Bosnian, Croatian, Montenegrin, and Serbian are synonymous names for Serbo-Croatian, a name used by linguistic academia world-wide with the exception of scholars in each of the Serbo-Croatian-speaking countries, at least a significant number of them, who cannot reach an agreement regarding the name of their standard language. Slovene has a less mutual intelligibility with Serbo-Croatian and is always translated in Serbo-Croatian-speaking media (TV and radio), so it is better to stick to the Serbo-Croatian varieties or to recur to English.