Modifier letter double apostrophe

So, you know how we put little marks above or below some letters to change the way they sound or to give them a different meaning? Like the "hat" on top of the letter "é" in "café" changes the way we say it? Well, the modifier letter double apostrophe is kind of like that.

It's a little mark that looks like two little apostrophes (') stuck together, and it goes above certain letters in some languages, like Vietnamese and Hmong. When it's there, it changes the way the letter sounds. For example, the letter "o" with the modifier letter double apostrophe above it makes a sound that's kind of like "aw" in English.

Sometimes, the modifier letter double apostrophe can also give a letter a different meaning. In Vietnamese, for instance, the letter "o" with the modifier letter double apostrophe means "grandfather," while without it, it just means "oh."

So, yeah, it's just a small mark that can make a big difference in how we pronounce or interpret certain letters in certain languages.