New answers tagged kana-usage
Simply the stylistic choice to use a variant pronunciation. [tju], [tʃu], and [tu] are all allophones in English. Japanese typically uses [t͡ɕu] (close to [tʃu]) for Neptune because it's the closest match to the native phonological "rules". This atypical (much more so than トゥ) form is just "artistic freedom" IMO.
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