What are you saying? It's NEVER ok to use even minimal fantasy language unless you publish an entire lexicon?
Oh, and it's called conlanging. I can do it. I know exactly how it's structured and why would I need to explain it? The sentence I wrote was for fun. I don't write full sentences of it in any of my projects. It's a hobby. And to the OP, this - ... rather one to be hinted at but only a handful of words actually used (A Song of Fire and Ice) ... - is what you should aim for if you're interested in language creation and want to incorporate it occasionally. To use words for Man,Woman, Children, Sword, City, etc, like you proposed, one doesn't need to know proper clauses, syntax, etc, of course.
I find it rather useless to include phrases to make it seem like you have a "kool fantasy languije i mad myself". Words I can understand, it does show it's a different world. But seriously: Whom do you write for? -English speakers (presuming you are writing in English) What do they understand? -English What do they not understand? -The Ancient tongue of High Sporkanese What, then, should you write in? -High Sporkanese No! -Yes
It's OK to use a word or a phrase here and there, such as having a character scream "Ma'Sprekoka!" if she stubs her toe and cue reactions from those around her. Or maybe a scholarly character can read out an ancient inscription on a tomb, "Muwva shelauo vinaba sprekia...it means 'Let the One with the Gem Enter with Caution'. Roughly translated, of course." However if you spend pages upon pages of dialogue where they speak in the language no living human on our planet could hope to understand, that's a problem. But use sparingly. Readers will already know this isn't set in our world, so you don't have to have them break into an ancient tongue every other scene.
I am agreeing with you @Link the Writer However, it is a very narrow minded viewpoint dagolas has. One that isn't shared by all readers. I've read plenty of books translated from other languages where certain words, perhaps pertaining to specific cultural references for instance, could not be translated and were left as is. I certainly didn't find it disruptive. I've read books where French characters have spoken occasional phrases that I didn't understand. Didn't bother me. It was part of the character. The OCCASIONAL word in whatever language you choose, is in no way the equivalent of a "kool fantasy languije" that nobody cares about. On the contrary, it can be a useful tool for informing or reminding the reader of a character's cultural background and lends authenticity when done tastefully. Nobody's suggesting pages full of it. OCCASIONAL.
Personally I like when books have a fantasy language, hence why I implemented a little in my book. I find it helps make the cultures of you world more distinct. I am aiming to emulate Martin more than Paolini. A Song of Ice and Fire has words from different languages but never really shoves them down your throat. Khal, khaleesi, Dothraki, Valar Morghulis, valar dohaeris. That's pretty much it. I did incorporate a little bit of Paarthurnax, from Skyrim, into the character that speaks the most in my language. Even then it's mostly just a random word a phrase is very rare. The rest of my characters mainly just use it for curses or to call my MC a pansy. No one speaks in it fluently it's dying, like Latin, there are a some who can speak it fluently and a few who know a few words. '
The most commonly used device for this is inserting the foreign word in a sentence where the sentence would otherwise make perfect sense to the reader, thereby implying the meaning of the word and assisting them to learn the language as they progress. So saying that, it's not as if English is totally replaced by the new language by the end of the book. Although that would be a neat trick if it were done. With regards to secondary languages, unless you are an extremely skilled linguist it's hard to pull off convincingly. Often writers use a language which is not in common use amoung their readership, but is nonetheless a real one. Cymric, Arabic, Hebrew, Old English etc.
Khal, Khallesi, Arakh, Khallasar, etc. We see a bunch of Dothraki words. Valar Morghulis. Valar Dorheris. We see a few, and George RR Martin never created the languages. Just do it well if you're going to make a new language.
I rofl'd on your post, but I, too, have this fantasy-language-thing which is somehow necessary for creatures in my novel. However, I am confused if I shall/should include a fantasy language in my novel.
Basically, you don't want your fantasy language to hinder the readers' understanding and enjoyment of the book. If they're not going to understand a significant section of important text, or if they'll have to flick to a dictionary in the back of a book to look up what a certain character has said, then you've gone too far. I think adding in bits of languages here and there though is a good thing. Using honorifics, greetings, curses and the like in fantasy languages adds that little extra depth to your work and readers should quickly grasp what they are and when they are used, even if they never actually know what it actually means.
This is a rather extreme viewpoint - all or nothing. There is no need to write a whole language or none of it. The basics are phonology and syllable structure (I could throw in stress), which should get people to a point where they can create consistent proper nouns for the names of people and places. While many conlangers prefer to aim for phonologies, etc, different to their native tongue to avoid creating an elaborate cipher, it is best to avoid sounds that are too exotic. Names are likely to be the best way to add flavour to a fantasy world, to show that English/French/Arabic/Japanese isn't actually being spoken, it's just being translated into those for the reader's sake, but not all words can be translated because there isn't an exact match, and those are names. Even in real world languages, names cannot be translated exactly; my name, Andrew, is Andoryu in Japanese, quite different. Of course, names can and should be transliterated, and taking my name as the example, it goes from using the underlying structure of the English language to using the underlying structure of Japanese so Japanese speakers would be able to understand it easier. There's no need to be an expert linguist, all that is needed is research - and in the age of the internet, it really is out there for people to find. It takes years and a lot of effort to create a decent conlanguage, and most of it can't be used because it will hinder the story, so it's best to focus on the basics and keep the rest of it for oneself and the conlanging community.