What's the best way to show a character speaking a foreign language in a fiction manuscript? Should the foreign words be italicized and include a translation? Should it just be included in the sentence and try and make sure the reader can guess at the meaning by using the surrounding sentences and words? Is there another way that's not coming to mind?
You have two options depending on context:
1) If it's a quick exchange and can be figured out in context, put the foreign language in italics.
"As-tu le livre?"
"Yes, I have the book here."
"You filthy p'taQ!" B'Elanna snarled.
2) If it's a quick exchange without context, put the translation afterwards and italicize that.
"Pour ma peine, ma punition, je tourne en rond," he sighed. For my pain, for my punishment, I pace in circles. Now Picard understood.
"Qa'pla!" Success! the Klingon shouted.
In any case, I would not have more than one or two exchanges in a foreign language. Either use a tag like "she said in French" so the reader realizes the characters aren't speaking English, or note in narration "they discussed the matter in French for some time, but as Malcolm didn't speak the language, he had to wait for a translation."
The way I see it, if the foreign language usage is important to the story, then use it in italics. If not, just avoid putting it explicitly in the text.
For example, assume you write a fantasy novel in which Elves always add the word Ur-Sook when addressing little children.
"Not now, Ur-Sook!" the Elf waved the child away.
"Not now!" the Elf waved the child away.
The Elf barked something in Elvish and waved the child away.
If you just wanted to make sure the reader understand that the Elf is busy, the second and third examples will do.
However, usage of the the first example can help you develop your story.
The reader will probably wonder what Ur-Sook means, and maybe guess this is the child's Elvish name. But then you can twist it around by having a mature Elf use that word when addressing another mature Elf, which will lead to a fight among the two...
In this case. the usage of the word and its inclusion in the text is important, so the first example is more appropriate.
Try to avoid using another foreign language as a stand-in for the language you're wanting to portray (like, say, using Swedish as a stand-in for Romani, as was done in Thinner). I'd treat that as the most absolute requirement.
Try to avoid long passages in another language. If you're finding yourself using much longer sections than "a sentence", it will probably be too intrusive.
For single sentences or shorter, provide something along the lines of a translation. This should probably be to the level of understanding of the scene's viewpoint character.
"Ruttna som en banan!", shouted Gunnar.
Elyse could tell that he was agitated, he only ever spoke Swedish when at the limits of patience. She didn't know if she wanted to know what he was actually saying, it was probably obscene and perverse, as stressed as he was.
FWIW, he's shouting "rot like a banana", pretty silly as an interjection, but at least not very offensive.
It is possible to use multiple languages even if you actually don't by flagging them in dialogue tags. This is good when who speaks what language(s) is important in the narrative. You can put the inter-language confusion in the dialogue and the speakers' actions. You can also use this to play with mis-translation, either deliberate or incidental.
If you know what you're doing, you can also use idioms differently to subtly indicate a different langauge. For example, in one of my fantasy worlds, I characterise one of my languages by limiting contractions and by repeating verbs in a way that is not usually done in casual English.
This technique as also a good out if the languages are fictional, or if you, the author, don't actually speak one of them.
I have often wondered the same thing. Recently I read a few books online that incorporate different languages into their stories, usually with dialogue.
There are two simple techniques that I learned to solve this issue of having the reader confused with what the character is saying:
After the main dialogue in another language, write the translation in brackets and italics. Example: My mother scolded me once I dropped the precious Vase which was so valuable. She yelled, "Neeku emaina piccha? [Are you crazy?]"
Another way to incorporate some sort of translation would be for a character in the story to translate the words in another dialogue. Example: My mother knew that my boyfriend didn't know Telugu, but it was the only language she knew. So without hesitating, she greeted him saying, "Bagunnava abbayi?" Karan tapped my shoulder and whispered to me, "What did she say?" I whispered back, "She asked 'are you fine, boy?' in Telugu." "Oh," he then faced my mother, "I am good Auntie." Then my mom asked me what he told her and I translated, "'Nenu bagunnanu Auntie.'"
Foreign languages can add a lot of flavor to a story if used in moderation. Don't put entire dialogues in foreign languages and consider the purpose and function of having those languages there.
Foreign languages are very present in the fiction I write. Some of my fiction is about American ex-pats abroad, another work of fiction is set in New York, which is a polyglot city. In both of these situations, I see language as a flavor of the landscape, and it's not important that the reader understand them. (Bonus points if you do.) The main rule I use is to never put essential dialogue in another language. If you are dealing with a code-switching culture such as Spanglish or the way Lebanese switch between Arabic, English, and French—often mid-sentence, it works especially well.
"Ma shifto bl after-party; think he went to go akel wa7ed with his boyfriend. Kan akho manyukeh! That Iranian DJ from Off On played a set at the hotel. Fady got some K kteer awiyyeh."
My favorite example of using foreign language to flavor a novel is the underrated classic Kaputt Goes Europe by Curzio Malaparte. As the Germans occupy Europe, we find snippets of Ukrainian, Russian, French, German, etc. Amazing prose too.
Haitian Creole to English:
They said, "Jodia nou pral beyen. Eske ou vle vini tou?" ["Today we are going to take a bath. Would you love to come too?"] Anticipation oozed from their eyes.
They said, "Jodia nou pral beyen. Eske ou vle vini tou?" (Today we are going to take a bath. Would you love to come too?) Anticipation oozed from their eyes.
This is what my two editors came up with for my manuscript.