Before the main post, 2 facts about myself:
1. I am learning Chinese and Japanese
2. Unlike the stereotypical version of a white American, I can usually tell the difference between East Asian nationalities just by looking at them.
Anyhow, I have a neighbor who's East Asian. For some reason, I thought he was Japanese. I saw him tonight and greeted him in Japanese,"Kombanwa". He gave me a nasty Look and I realized my mistake: He was in fact, Chinese.
He must think I'm a total racist!
What do I do?
Also, was it racist of me to try to greet him in Japanese seeing as I thought he was Japanese?
It's not racist per se, but here's what you need to know coming from someone who is Asian and has been on the receiving end of that before.
It doesn't really matter what he was. Don't go round greeting any Asians in what you think is their mother tongue. Even if the person was Japanese and you greeted him in Japanese, it can come across as if you are mocking the person and trying to make some Asian/ Oriental sounds or using the one or two bits of that language you picked up (he won't know whether you are actually learning Japanese or not).
It's a bit like if you see someone German and spout out some words you heard in a WWII movie. Not quite as bad as saying "Heil Hitler", but if the Chinese person has been born and brought up in the US or the West, and you naturally assume that he speaks Chinese (or Japanese in your case) as his mother tongue, you can be offensive. He might be as Western as you and might not know a word of his so-called "mother tongue".
If he doesn't know any Chinese or Japanese at all, then he won't know the difference between whether you were actually speaking in one language or the other. The offence won't be that you assumed all Asians are alike, because he won't know what you said anyway. To him, all it will seem like is that you're then making some mocking Asian words based on the way he looks.
So there's two potential offences here: not only can you seem like you're mocking him, but you're making assumptions about him based on his appearance.
The best thing to do would have been to just greet him in English and begin a conversation, instead of blurting out a Japanese word as your ice breaker.
So maybe not racist, but certainly ignorant on your part. If you want to smooth things over, you should go and explain that you are learning Japanese, that you don't think all Asians look alike, and that you made a genuine mistake, and don't want to come across as racist. You should even acknowledge that you did make an assumption about him a) that he was Japanese and b) that he spoke in a different tongue as his first language and that you can see how it can be perceived as very ignorant and even racist.
And one more thing: if you begin a conversation in English with him (or any Asian) and he gives you a bewildered look and says "sorry?", do NOT naturally assume he didn't understand you and launch into Japanese or Chinese to speak to him. He might have just not heard what you said or you weren't being very clear. You wouldn't make that assumption with a white person but would just repeat yourself.