https://www.w3.org/2007/02/turtle/primer/
Audio (etc) plugin format that uses .ttl:
https://gitlab.com/lv2/lv2/-/tree/master/lv2/core.lv2
https://gitlab.com/lv2/lv2/-/tree/master/schemas.lv2
https://drobilla.net/software/sord https://drobilla.net/software/serd
drobilla has mentioned that, if there was a C JSON-LD lib, that might be enough to warrant an LV3
For more: https://github.com/lv2/lv2/wiki
P.S. not many people know that LV2 does modular synth style CV https://linuxmusicians.com/viewtopic.php?t=20701&p=112242
https://www.w3.org/TR/n-triples/
https://www.w3.org/TR/n-quads/
which can end up as the easiest formats to work with sometimes.
There are tools like 'rapper' and 'serd' to convert to and from the various formats.
My dabbling in that direction stopped at five (name-spaced) identifiers.
Effectively extending n-quads with an "edge" identifier. Mainly to eliminate blank-nodes but it handed the optional language & typing just fine and more importantly for my use case allowed for the uri to be expressed as curie (namespace) and a local_id each in their own column.
Which has a lot of wikidata specific stuff but allows to get the basics.