Latin Capital Letter Y with Hook Above

Latin Capital Letter Y with Hook Above at U+1EF6 is an uppercase Latin letter Y carrying the Vietnamese hỏi tone mark. It is part of the Latin Extended Additional block and functions as a precomposed Vietnamese vowel letter rather than as a separate symbol. Its everyday use is in Vietnamese orthography, where Y can serve as a vowel and the hook above marks the hỏi tone, a dipping-rising tone in the standard six-tone system. The capital form appears at the start of words, in names, headings, signs, and all-caps text; for example, it is the uppercase counterpart of the letter used in Vietnamese words such as ỷ. The character is also important in libraries, passports, maps, and databases that preserve Vietnamese diacritics in personal names and place names. If a system strips accents, it may collapse Ỷ to plain Y, losing tone information and sometimes making words or names ambiguous.