I know you can add the suffix ございます to おはよう to make it politer, but can you also do this to こんばんは and こんいちは, and if not, what would be the best equivalent?
To add onto above answer, the reason you can add ございます only to おはよう is because ございます functions as a polite version of です.
おはよう(お早う) means early, so to add politeness, you can throw on ございます on the end, and it fits right in the slot like です would.
こんにちは and こんばんは however, cannot have です at the end because, こんにち (this day, but use 今日 for anything besides this greeting) and こんばん (this evening) are the subject and the は is actually a particle.
You can really feel this if you try a sentence like "私はです" or "私はございます". です needs to have something before it besides the particle :]
こんにちは and こんばんは however, cannot have です at the end because, こんにち (this day, but use 今日 for anything besides this greeting) and こんばん (this evening) are the subject and the は is actually a particle.
I understand, but is there a way to make こんにちは and こんばんは politer or do they always stay the way they are?
こんにちは and こんばんは are fixed phrases that are abbreviated from full sentences with the same endings which ポールおじちゃん explained, so you can't really alter it. You don't need to worry about adding politeness to it. It would make much less sense to repurpose the sentence and adding another sentence or redundant ending that would make it grammatically nonsensical.
