1) the names of things with no equivalent word in English;2) the phrases spoken by the native speakers;3) the phrases spoken in reply by Earth characters who know the native language;4) the words/phrases which are added here and there to help lend authenticity to the scene.
I recognize that having extensive passages in other-than-English is tedious for a reader. Thus, I try to limit myself to following a few rules when writing with alien languages (or Earth languages other than English, for example the Hindi spoken by Indians in my India novel about tiger hunting).
Rule 1. When the character hears spoken words which happen to be in the other language, I write out some of it. This is literally what the character hears, even if he doesn't understand it. I can then explain what it means, as appropriate to the scene. For example, an announcement over a loudspeaker.Rule 2. When a character literally speaks in a language other than English - because the character does not know English or chooses to speak in another language - I either provide a simple unobtrusive translation or otherwise tell the reader what was said. I do not want to give up the authenticity of the scene by avoiding the foreign language. For example, whenever it is vital that the character speak his own native language (which I give at least a clue as to what it means).
In THE MASTERS' RIDDLE, there are intelligent beings from several worlds. I give each its own language although for the most part I tell the story in English. How can they communicate with each other? An advanced species would have elevated means of communication. First, there is vocalization...which is not going to be understood no matter how well heard. Next is the attempt to communicate visually with facial expressions, hand gestures, and making marks on a surface or circumscribing designs in the air. I have them doing the 'Vulcan mind-meld' in some instances, where one being touches the other and through that neural network connection they can communicate. And a few other clever methods.
“The Process is what you do with your mind to tear space apart and project body through tangent opening. Do with power of mind, which can be greatest force in the universe. Bio-chemical, electro-chemical energies created in the brain of an advanced creature, applied to engineering problems, can move mountains—sometimes planets. Or, as you say on your world, to ‘raise the stars’.”
Toog’s face flashed bronze. “sT’n Ra’q.”
“You remember expression from childhood? Took from your mind, from memories of childhood training, so can understand. Is true. This power, when focused on right spot and increased to right magnitude can rip curtain between two sides of universe. At such a moment, while rending this curtain, step through to other world.”












