Which is easier for human perception: type of variable before or after its name?
I don't think there is any research (with good methodology) on this. The language I'd most expect to have actually thought about this and made an empirically-based decision is the Quorum programming language. It uses a "type before variable name" approach (though it does put the return type of a method declaration after the parameter list). However, what I believe is the primary source for the language design decisions, An Empirical Investigation into Programming Language Syntax (available via the first author's web site), does not mention this aspect or suggest that it was studied in the research reported on in that paper. There is other research by that group and research by others that was used to design Quorum, so it's possible it is covered in that other research. I haven't read it all. You can try contacting one of the creators of Quorum and asking them if they made that decision based on empirical research. If you do and you get a positive response, I would highly recommend self-answering this question with a reference to the research.