Well i need to know how long it will take to develop an entire language like Tolkien's Sindarin. Cause if it only takes a few years i will make more fully developed languages. This is for my fantasy novel, and along with this im trying to be as original as possible with it.
How much time do you have? lol You can make it overnight if you're smart or it may take you years. It'll be difficult but if that's what you like doing more power to you.
If you are avoiding trying to make an English cipher and you want to make something like Tolkien, you will definitely need a few years and a decent background in Linguistics (self-research does count; you don't need an actual college degree in it, but you will need to do a lot of studying and research) so that you make something actually original instead of copying off English and/or your native language. Although I myself find conlanging kind of fun, think carefully about whether you really need a language with that much development, and whether you want to waste that much time on it. I've been conlanging for almost a decade now, working on several projects, and so far I only really have one language that I can actually converse in - except that I'm going back to fixing it for now. Thus, conlanging for a creative writing project is an arduous and time-consuming task. You can still make a relatively "original" conlang without going through all that work, by only adding in a few nice linguistic features but otherwise basing the language on languages you otherwise know - at the least it won't be a cipher of English or something. Still, if you are serious about conlanging, I highly recommend that you join a conlanging forum (there's several of them online, and they are pretty active), so that you can get advice and help from more experienced conlangers. Remember, however, that interesting as conlanging can be, you have to consider your priorities - are you here to make a novel, or a language? For Tolkien, in fact, it was the latter, which is why I think it took him a long time before he actually published his stuff. I myself only work on languages when I'm stuck on writing, and need a bit of a break.
Im only 14 and the thing the languages of the real world have lots of diffirent types of structure and syntax. It's alot to take in, but it can be done in a few days if i was a language professor but i might need to do alot more research and then write down the basics and move on from there...
If you don't know what you are doing (like Tolkien did), I'd avoid creating a language and just use some key words here and there for flavor. Like cyberxkhan said, you're basically going to create a cypher of English unless you are schooled in language and devote a lot of time to the creation. I'll add that you'll either end up with a cipher or a complete mess (or both).
Im working on a Novel trilogy or saga (knowing how big my world is i won't know until i finish the 3rd book) and im making languages so i can make the world feel more real and different. But your suggestion about conlanging fourm sounds like a splendid idea, and yes it will probably be a massive commitment, but i just want too see if i can do it, but if it's alot harder, i will put my time and effort to have atleast one complete language.
I'm going to agree with everyone else here. I my self have MC's who are from diffrent countries in this/our world and I have deticated years, littlerly years to learning these languages. even though I use maybe 50 forigen words total in the novel. Inventing a whole new language does two things first you still have to exsplain the whole thing in english or your native language to the reader, secondly, I know people who would spend hours sitting down spotting the misusages, and other errors that you have in the work. Why? because they think it's funny, but that is a side note really. It might be better to invent a few words/phrases to use as icing on the litterary cake. just my two cents.
And to be honest, as some others have indicated, you actually don't need as much as you think for a novel. I myself only use a handful of words and grammatical structures from my conlangs - well, mostly one at a time, anyways, since most of my stories mainly take place in one conculture. It's fun conlanging, it's rewarding, it's educating, and I think it's certainly fine spending a good amount of time on it - especially when you need something to do while taking a break on working on your novel(s) - but make sure you don't lose track of what you actually want to do.