A comunidade se inscreve e se reune pra ajudar na tradução do Steam. Qualquer um pode participar. Basta se inscrever aqui: http://translation.steampowered.com/
Tem a comunidade no steam também: http://steamcommunity.com/groups/sts_brazilian
Só lembrando que a comunidade é só um canal a mais. Pra participar mesmo tem que se inscrever no site do Steam.
Lá mostra o progresso de todas as traduções. Pena que a do Brasil ainda está no começo. Mas acho que com a divulgação a galera vai aderindo mais, e a tradução vai caminhando mais rápido.
Steam Translation disse:The Steam user community consists of over 25 million people around the world who run Steam in one of 21 languages. We do our best to translate everything for everyone, but we admit it's difficult to keep pace. With your help, Steam can now become fully localized in each of the 21 languages we support.
As a participant in Steam translation, you'll have access to all text elements within Steam's Client application, Store, Community, and even Valve's games. You'll have the tools you need to view what items are in need of translation, suggest translations of your own, and submit feedback on other translators' work. To participate, simply link your Steam Account with this site. Once logged in, you'll find all the information you need to get started. As you gain experience in providing translations and submitting feedback, you may become a language moderator yourself, guiding and approving other translators' contributions.
Below you'll find a list of current text elements, or "strings" in need of translation, plus a graph displaying the overall translation status of all language files within Steam. You can see there's much work to be done, and we're glad you're here to help - Your contribution to Steam translation will impact users worldwide.
Deixei o tópico oficial pra quem for participar, se tiver com alguma dúvida de tradução pede ajuda aqui, esse tipo de coisa.