These days all variables created by me, in any language, are in descriptive_snake_case. I just can't see any reason to use anything else.
Non camelCase variables and CamelCase classes in Java for instance would really feel out of place to me, whereas using the same case conventions for some ruby code would feel equally 'wrong'.
When it comes to conventions like this, I don't think there's a substitute for having a "when in Rome" attitude. If you're writing some greenfield code, Rome is all the other projects in your language of choice. If you're adding some functionality to an existing piece of code, that existing piece of code is Rome.
Yeah, this is a good point. I come across as gung-ho in the parent but I have to admit I do submit to the "when in Rome" effect.
That said, if Rome is an absolute shambles, I might feel empowered to start anew ..
I usually try to find some sort of dominant naming scheme to follow and clean up old code left and right, but yeah, sometimes starting anew can be the only sane thing to do.
So, snake_case in Python and camelCase in JavaScript (with classes being initial Capital in both).
For identifier 'camelCase' use '驼写'
But then again, I have no problem going into a badly formatted hunk of code and fixing it. I have, on occasion, reformatted entire source directories because the original sources were so terrible.