Vietnamese Braille
Vietnamese Braille is the braille alphabet used for the Vietnamese language.It is very close to French Braille (and thus to a lesser degree to English Braille), but with the addition of tone letters.Vietnamese Braille is known in Vietnamese as chữ nổi, literally "raised letters", while electronic braille displays are called màn hình chữ nổi.Apart from đ (which is brailled as ⠮[1] and the addition of five tone letters, the Vietnamese Braille alphabet is nearly identical to French Braille: the only other difference is the substitution of Vietnamese ư ơ for French ü œ, and the dropping of those letters which are not needed in Vietnamese.However, because of the tone letters, the design is different: Vietnamese Braille has separate letters for vowels and tones, so the French Braille letters for é à è ù are not used; they are written instead as tone ◌́ or ◌̀ plus the vowels a e u.