Combining horn

Use Telex ow/uw, or VNI o7/u7.

In Telex, ow makes ơ and uw makes ư; in VNI, o7 and u7 do the same. Add a tone key or number afterward when needed.

Some smart Vietnamese input methods move a modifier typed at the end of a word onto its vowel. Prefix it with a backslash when you need the keys to stay literal, as in o7.

what does combining horn mean?

It distinguishes ơ and ư from plain o and u.

The horn changes the vowel, not its tone. A separate Vietnamese tone mark can sit on the same vowel; forms include ớ, ờ, ử, and ự.

In Alexandre de Rhodes’s 1651 catechism, a Christian teaching book, the horn appears in blời and những. Chữ Quốc Ngữ, Vietnam’s Latin-script writing system, took shape as Jesuit missionaries, members of a Catholic order, combined and refined spelling traditions alongside Hán-Nôm, Vietnamese writing traditions using Chinese characters and adapted forms. The system first served language study and Christian teaching; later it carried philosophy, poetry, and politics as it became Vietnam’s national writing system.

why does combining horn look wrong?

Its display depends on a base letter and a capable font.

This is a nonspacing mark: it attaches to a base letter instead of taking its own space. A font or text-layout system with incomplete support may detach or misplace it, or show a missing-character box even when the text sequence is intact.

The horn attaches to o or u; Vietnamese hook-above, acute, grave, tilde, and dot marks add tone. This character is a piece of Vietnamese spelling.