@AndyPage, thanks for the great suggestion. An approach similar to yours can work well in Text Blaze:
{letters= ["à":"a", "á":"a", "â":"a", "ã":"a", "ä":"a", "å":"a","ā":"a", "ă":"a","ą":"a", "ç":"c", "è":"e", "é":"e", "ê":"e", "ë":"e", "ì":"i", "í":"i", "î":"i", "ï":"i","ñ":"n", "ò":"o", "ó":"o", "ô":"o", "õ":"o", "ö":"o", "ù":"o", "ú":"u", "û":"u", "ü":"u", "ý":"y", "ÿ":"y"]}
{word="catàáâãÿåúăąbat"}
{=join(map(split(word,""), (l)->letters[l] if includes(keys(letters), l) else l),"")}
@Jade_Heilmann - does this work?