To go a bit further.
There is no formal concept of a group and it can mean radically different things to different people. There are cases of public adverts leading to a group, others might have spoken on various boards, IRC and whatnot for years and worked on projects together during that, rather than mess around with user names they get a group name and you are not likely to get in there.
Still around here, as opposed to places that might deal in games with premade tools that do a lot to them, you will tend to have to have valuable skills. In translation this will tend to mean language skills or hacking skills (or both if you are a show off). Some others can get by with art and level design, though in both of those cases you are going to want to know how the system works such that your art and levels work within it -- Picasso could arise from the grave and as he probably would not have a clue about how palettes work he would be useless to me.
What we often see are people that want to be a project leader and contribute no tech or language, maybe just be a "series expert". Avoid such groups as they so seldom go anywhere but will often sink a hundred or so hours of your time before they implode. More than one person has actually managed to gain enough skills to do something (the first major hurdle) and then fell prey to such a group and drifted away because of it.
With all that said your skills don't need to be tip top to be helpful -- part of playing with language tends to be making a font/encoding table. If there are thousands of characters (and Japanese has thousands after all) often the only sane method is to manually pair characters. If you can recognise things and help that along then there may well be space for you to help out. Similarly requests to "translate this game" go nowhere, "I have this script I have extracted and started to translate, can you help with insertion or a variable width font" is a different matter entirely.