Visited Japan for a month and I am obsessed.
おはようございます、うさぎさん。 Sorry for missing you message, To answer your question, a little vowel (such as ィ) is used when you have characters like ち、し、つ、etc... that have an altered sound but you want the pure sound. your example was a good one: we can't say パーチー because that would be (paachii) the ch sound isn't there, so instead we used テ paired with the little vowel. the え column is usually used simply because it has no irregular characters. (all of which consistently lie in the い and う columns) so now we get: パーティー (paatii) Hope this helps
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