Is the preposition 'i' before 'fi' here a long or a short vowel sound? Based on the Wiktionary pages for 'iddyn' (and 'iddo' and 'iddi'), it is a short vowel (I always pronounce Welsh words as the North Welsh do to remember which words are spelt with 'y'/'u' and which ones are spelt with 'i'). However, that could just be because it is part of a longer word.
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