Well, I am applying for a bilingual job and I need some help improving my English over the next 2 months. The job is related to tourism: I live in La Fortuna, which is a small town located in Alajuela, Costa Rica. La Fortuna is famous for its Volcanoes, one of which is an inactive one called "Cerro Chato". Two of the beautiful things that make Cerro Chato an awesome place for hiking are its Turquoise Lagoon and the La Fortuna Waterfall that is now on one of the ancient lava flows.. The other volcano is called "Arenal" which is the source of heat for many hot springs across the town. A few years ago, people could see lava flows on the hills of Arenal ... but unfortunately, that has not been the case since 2011. 

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Place names (nouns) should be capitalized in written English. Other than that I think I could understand your meaning with minor issues. I think you can always add more information as a tour guide if the places are famous (ie. with a quick Google search, Catarata Fortuna has it's own name and history so it's not just any regular waterfall and should be identified as such (La Fortuna Waterfall)). It should be a very fun job! Wish you the best of luck.

(edited for clarity)