How did Ron speak Parseltongue and re-enter the Chamber of Secrets?

Although 'The Deathly Hallows' was overall an excellent conclusion to Harry Potter's saga, there were moments within the book that felt infuriatingly lazy, like Rowling was whipping the plot along irregardless of any holes she made in it. For me, the very worst was when Ron gargles at the entrance of the Chamber of Secrets- and succeeds!- so he can get some Basilisk teeth to destroy a Horcrux (which are conveniently vulnerable to this venom).

This is, by itself, an amazingly slapdash deus ex machina, but even worse is how it is completely inconsistent with the earlier novels. First and foremost, Parseltongue is not just a language, but a magical ability that can only be learned through inheritance or magical means (Potter being the sole example of the latter). This is firmly established by the fact that even Dumbledore, the greatest wizard of all time and a polyglot, is completely unable to speak it despite understanding it perfectly.

Without linguistic knowledge nor inherent ability, the chances of making any kind of coherent sentence (let alone the right one!) would be incredibly slim even in the case of mundane languages; it would be like gibbering at a Filipino in the hope that what you said was fluent Tagalog and didn't insult their mother.

Other baffling issues less relevant to my question are thus; even if Ron had somehow unlocked the gate, how did he make his way down? In the second novel, Lockheart's foolery demolished the main tunnel to the Chamber, making it impossible to access or leave; the fact that the teeth are still there also implies that the Chamber wasn't excavated and the rubble cleared in the interval. Granted, he could have tried Apparating, but then he wouldn't have needed to fake Parseltongue to begin with.