

Not necessarily.
You’re kind of talking about two different things that are somewhat interchangeable. First you have a username which is used to log into a network or system. Second you have a forum/chat handle which is used to identify an anonymous or semi-anonymous user (e.g. CerebralHawks for me). I don’t think it’s strictly necessary for a forum handle to be pronounceable, but it’s easy to read mine and call me that, or just “Hawks” or “Hawk.” If it’s not, the mind isn’t going to retain it as long (this could be a good thing) and it’s hard to say, so it’s hard to address.
Usernames absolutely don’t have to be. Forum/chat handles should be, but it isn’t necessary.














I’ve seen handles in kanji — I assume Japanese, could be Chinese. Some browsers will translate that if they can. At least to something you can say (if you don’t know how to say those symbols, that is). For example, people whose first language is English can say “konnichiwa” — the Japanese word for “hello” or “good day” written in Romaji, which is Japanese using the Roman alphabet — but they wouldn’t know how to pronounce こんにちは — it’s the same word. So you can look at that in my message and say “konnichiwa” out loud, but if you happened upon it in a week and you’ve forgotten I said this, you probably won’t recognise it. But, you can highlight it, long press/right click and search your favourite search engine to find out what it is.
(Side note: I do recognise は which is pronounced “wa.” It’s part of the title of my favourite film, 君の名は。 (Kimi no Na wa., or “your name.”) I also recognise の when I see it. This was the first one I learned — because it looks like a fortune cookie!)