Why chag sameach and not hag sameah?

Answer 1

Any spelling of a Hebrew word with English characters is going to a guess. Hebrew has its own

alphabet, and has never been spelled with English characters. There are even a sound or two

in Hebrew that don't exist in the English language, and for which no English characters exist.

So anybody using English characters is free to spell Hebrew words any way he wants to.

The goal should be to use a spelling that will convey as faithfully as possible the sound of the

spoken Hebrew word.

In the case of the greeting for "Happy holiday", the very first sound of the first word, and the

very last sound of the second word, are both a sound that doesn't exist in spoken English,

and can't be written with any English character. It's close to the the sound you make when

you whisper the word "key". It's also close to the "ch" sound in German, so it's commonly

written as "ch" for the English rendering of the Hebrew words too. But as we said above,

there's no 'official' system of rendering the sound of Hebrew in English spelling ... as there is

for 'Pin Yin' Chinese ... so once you're confident in your pronunciation of the Hebrew words,

you're certainly welcome to spell them any way you feel is appropriate in English.

Answer 2

It's a departing greeting exchanged during or just before a festival, particularly Passover,

that means roughly "a joyous and kosher festival".