I won’t pretend that Constructed Languages aren’t a lot of work. To really get into it, to do every element of it, you have to love it. And if you have a world full of different cultures, different languages…. that’s it’s own project completely, and not one you’re likely to want to engage in if you actually want to, you know, write stories.
Especially if you’re not going really need full languages in your stories. You probably won’t.
What you will need, though, is a certain degree of linguistic verisimilitude, so that names of places, people and culturally unique terms will seem like they come from the same language base.
Easiest way to do that is to construct a phonology. A phonology describes what sounds can be used in the language, and how syllables are constructed. With that information, you know what words can exist in the language, and to a degree, that’s all you need to know.
So, how to you make a phonology, especially if you really don’t know anything about linguistics? Fortunately, the internet has some tools you can use to make it easier. Right here is a webpage that randomly generates a phonology: phonemic inventory, syllable structure, allophony (the rules for breaking the rules, essentially) and sample words.
Now, the catch with this is, it’s all done in IPA: the International Phonetic Alphabet. You’ll probably want, for the sake of your writing, to figure out a way to latinize the words, so your readers can wrap their heads around it. Mind you, this will have nothing to do with how the language is written, whether it’s alphabetical or syllabic or pictographic. It’s simply figuring out how to write the words in simple text.
I recommend taking the sounds of your phonology and coming up with a consistent way to express each sound with a latin letter. It does not have to be a one-for-one. For example, your phonology might contain both a nasal alveolar (n) and a laminal nasal alveolar (n̻)– the difference between the two are subtle, and you might choose, for the sake of writing words out, to describe both with just an “n”. Of course, you could load up your latin approximation with diacritics (for example: å,ä,á,â and à could all represent different sounds), but if you do that, you should first understand what those diacritics mean and how they are traditionally used.* However, if you are going to use diacritics, I recommend you use them surgically and sparingly. Same with apostrophes. Fantasy authors love throwing those in, but you should only do it if it means something– for example a glottal stop or another sound that isn’t easily latinized.
So, with a phonology and a defined latinization of that phonology, you’ve got the tools to make words and names in another language that feel like they come from the same language, without having to overwhelm yourself with making up an entire language from scratch.
*- You might decide that å,ä,á,â and à represent various open-mouthed vowel sounds, but if the sound you match it to doesn’t correspond to how it’s typically used, you’ll just created confusion. For example “Ä”, the A-with-umlaut, is used in in Finnish and Swedish as a “near-open front unrounded vowel”, or “æ” in the IPA, so if you use “ä” for, say, an open back rounded vowel (“ɒ” in the IPA), your readers in the know will just think you don’t know what you’re doing. Or, more likely, throwing in diacritics because you look neat and foreign.