For the longest time, I have intended my work to have a Language - for the deep and secret mystic reason that a Magical Language makes your spells better because you feel cool and spooky.
For 'lets move away from the appropriation of Kabbalah in ceremonial magic' reasons, poorly-translated Hebrew is out; and Latin has been done - i know it but it brings a certain kind of brassy light or black mass energy which is only right now and then. Old English (a.k.a. 'Anglo Saxon') I love, big rumbly earthtones, but brings too much political baggage; contemporary Celtic languages - gaelic, welsh, etc - perpetuate a romanticism that contemporary language revivalists likely won't appreciate. My friends advised against Tolkien languages.
That rules out pretty much everything, but I keep finding myself drawn to Proto-Celtic - or possibly Proto-Indo-European. Neither language was ever spoken. They've been reconstructed by linguistic archaeologists. Languages shift over time, and if we understand how, we can look backwards in time.
Landweird.
An example of how this works from wikipedia:
In Gaulish and the Brittonic languages, the Proto-Indo-European *kʷ phoneme becomes a new *p sound. Thus, Gaulish petuar[ios], Welsh pedwar "four", but Old Irish cethair and Latin quattuor
The oldest language spoken in Britain, according to the internet, is a form of Celtic known as Brythonic (a.k.a. Brittonic, nowadays the preferred academic term, but the romantic folklorist who termed it Brythonic knew what he was doing; why even be a linguist if you cannot select words for their beauty and mystery. Brythonic it is.) But tread your way backwards and carefully, back down the tree past where the branches meet, and you will find the words that might have come before. Further back from that - the first, imagined Celtic - is Indo-European, the first-imagined language uniting language-families across the world, back into the darkness of deep forgetting.
I do not especially like Proto-Celtic. Unlike Old English, which makes me excited to speak, Proto-Celtic is a mix of overfamiliar and ugly. I find the tantalising names of gods-of-a-single-stone - Artaios, Belenos, Ricagambeda, Moritsagus - mighty. But my dabbling in dictionaries turns up nothing as powerful - perhaps because it's a language I don't know how to use
The word for 'land' is /φī-wer-jōnos/, but I am learning to love it. ɸ is a voiceless bilabial fricative - not like 'f', pronounced with the tongue-and-the-teeth - but a horse-huff of an 'f' as in 'pfffft!'. You have to say it out loud to get it, and while speaking pay attention to what the parts of your mouth are doing. It's soft like 'ph' - like breathing. Something meditative and strange about the struggle to make sounds new yet ancient
phferi-phfīwerianos - landbeyond - andīmiketo - bewilderment - brīwotelamon - earthfragment - morikommanos - seamemory - tanātanawo - thintime - leinesweida - the softplaces - dīglennelugrākandom - moonlightgatherer - mauknibargoses - bookbog - tuxslobrend - hollowhill - koudot - the hidden sound - mori-brano-rūnom - secretdiver - brixtās-uφo-dātū - spells in the sediment
This is not a history lesson; their service is as sound, and the sense of wonder that is speaking with a dead tongue in your living throat