There are a number of languages spoken in Steel universe, but the one you hear most often is Rimmic. There are quite a few Rimmic words in the books. It gets employed for swearing quite a bit for one thing, but I don’t always give translations (well, that’s sometimes why I don’t give translations). So, where does Rimmic come from, and how do I make up the words.
When Mankind went to the stars there were two big players, America (of course) and China (who needed the expansion room). As a result two primary languages could be heard on Human colony worlds, English and Mandarin. Federal, the language spoken by most Jenlay, developed from English and is actually very similar. You’d probably find it no harder to understand a Jenlay than a modern human from Liverpool (okay, maybe it wouldn’t be that hard). Rimmic developed from Mandarin. There are still quite a few Jenlay who speak Rimmic is a first language, and “Jenlay” is a Rimmic word.
And so, how do I make up Rimmic? I have help, namely Google Translate. Rimmic is created by putting text into Google Translate, setting it to Chinese (Simplified) and seeing what comes out. The important bit is that Translate has a function where it reads the words to you. I write down what I hear from that to create Rimmic words, rather than taking the literal (Latin alphabet) translation. I have no idea whether a Mandarin speaker reading the Rimmic in the books can actually understand what I’m writing, but it should make a sort of twisted sense.
Let’s take an example: Jenlay. Type “mankind” into Translate and you’ll get 人类, or Rénlèi. Press the little speaker button, however, and you hear something more like “jenlay.” Gopi actually looks like Gǒupì and sounds like “go pee.”
So, now you too can make up your own Rimmic sentences. Use this weapon with care.
Steel Beneath the Skin 
I”m so going to use this, thank Niall xD
As mandarin speaker (though I’m a white American) I thought as a reference just from reading, i.e. hannic or something like that, hanyu is Chinese and they are often called the Han people. I’m guessing this post title is ruhe shuohua rimmic, ruhe means how to and shuohua is speak, though technically you wouldn’t want to hua AND rimmic, as hua means words and is already used as the direct object from the verb shuo. But that’s a fun way to show the history, etc.