By this link I've found the answer how to distinguish difference among these functions: What's the difference between Carp/Croak, Cluck/Confess, and verbose options?. Unfortunately there are no any mnemonic rules to memorize their usage.

Too hard to foresee meanings of these four C-words, when they express something very similar each other. I understand that using them makes Perl lexicon richer even more poetical, but logic is definitely lost.

warn - carp (critisize) - cluck (sound like a chicken)
die - croak (sound like a frog) - confess (recognize about sin)
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Just for lulz. cluck looks like Russian клац (meaning something similar to click-clack a weapon). Croak is pronounced closer to кряк, which means in Russian to sound like a goose. In the other hand, quack is pronounced exactly like croak in Russian.

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