The Romajinator is a simple tool that converts Japanese Katakana into romaji, i.e., roman characters. Most western students of Japanese will have little use for this tool, since katakana words are about the easiest Japanese there is to read for native English speakers. However, for students of Chinese, it’s the opposite. Kanji is pretty easy to understand, but katakana is pretty alien. Since the vast majority of katakana words are actually loan words from English, they’re often easy to guess… once they’re converted into romaji.
サラリーマン -> sararīman -> "salary" man コンピュータ -> konpyūta -> computer サイエンス -> saiensu -> science プロジェクト -> purojekuto -> project メソッド -> mesoddo -> method
Most romaji vowels are pronounced fairly similarly to pinyin vowels. The big exception is the “e”. It’s pronounced fairly similarly to a “short e” in English. The “o” sounds somewhat like an English “long o”. Vowels with a macron bar over them are drawn out for a longer period of time. Doubled consonants represent a pause before the consonant. For example “setto” would sound like “se”, followed by a pause, and then “toe”.
The above is obviously a very rouge guide. For a more accurate idea of what words sound like, I recommend the Wikimedia Commons: Japanese pronunciation page.