la-HAR, or LAH-har?

I’m sort-of watching a show on volcanoes on The Science Channel. The narrator pronounces ‘caldera’ as ‘CALL-dur-uh’. I’d always heard it pronounced ‘call-DARE-uh’. Well, I looked it up over at dictionary.com and it says both pronunciations are correct. Then I noticed he said ‘LAH-har’. I’ve always heard that one as ‘la-HAR’ (or with only a slightly-accented second syllable). But when I looked it up on dictionary.com the accent is on the first syllable. Have I been mispronouncing it all these years, based on the way I’ve always heard it pronounced?

Lahar is a javanese-based word and according tothis:

Caldera is a spanish-based word which would mean that it follow the “VNS2” rule. (VNS2=if the word ends in a vowel, an “N” or an “S”, the penultimate syllable is stressed unless there’s an accent showing differently).

Post-thought: American english can pronounce things any which way they want to. We don’t generally incorporate the trilling rr in words like burrito for instance.