The Constitution has nothing to do with this. It constrains the Government, not private actors. And there’s no Constitutional right to a translation service.
You’re probably thinking about warrantless recordings of conversations and the reasonable expectation of privacy requirement. This doesn’t apply here.
The Constitution can definitely restrict the ability of the government to pass laws regulating behavior, and two-party consent statutes are definitely laws that regulate behavior. Whether the object level question is true is a different matter, but I would assume so given that you can point a camera that records audio at people in public at all.
Also, the US Constitution does constrain private actors, all the time. It bans slavery for a very simple example.
The Constitution does not forbid laws that require two-party consent to record a conversation. That’s what we’re talking about here.
The constitutional view of the 13th Amendment is that it withdrew from government the power to promulgate or enforce laws that allowed slavery to exist. If a slave escaped after the 13th Amendment passed, the government then lacked the power to assist the former slaveholder in capturing and returning him. Similarly, without the power to enforce property rights, there became effectively no property interest in a slave.
I’m finding a lot of literature from NGOs specializing in US jurisprudence saying the first amendment has been interpreted to protect public, obvious recording[1].
If I tried to draw up an indentured servitude contract, what federal or state laws would explicitly forbid enforcing it myself? If state laws, do all states have equivalent laws?
[1]: https://www.freedomforum.org/recording-in-public/
The First Amendment protects you against prosecution for filming the actions of law enforcement in a public venue. AFAIK it hasn’t been interpreted to void state laws that might forbid someone from recording a conversation between private individuals who don’t consent. The link you provided says as much.
How do you self-enforce an indentured servitude contract? Or any contract, for that matter? Only a court can compel performance or restitution for a breach of contract.