Programming languages exist so you can do something useful with the computer.

C is awesome and is probably as fast as you're gonna get without something like Assembly or machine code in hex.

In essence, this is the relationship between suppliers of a product. This concept, however, does not apply to FOSS.

See https://www.softwaremaxims.com/blog/not-a-supplier on why. FOSS software (should be) is provided AS IS, no promises.
Also see https://utcc.utoronto.ca/~cks/space/blog/tech/SupplyChainSecurityTwoVisions

• https://devdocs.io → language and tool docs
• https://www.programmingsimplified.com/ → resource for C and C++
• https://learnxinyminutes.com/ → primers on various programming languages
• https://choosealicense.com → help on choosing a license for a project