Q:

Can I put an executable in the user's PATH without admin-level privileges? 

I'd like to add Windows support to a language version manager I use.  
In its current macOS-and-Linux-only form, the manager downloads a few key language binaries/executables (compiler, linter, etc) to its own folder, with a subfolder for each version (manager/1.1/, manager/1.2/, and so on).  When you run manager use 1.1  or manager use 1.2, it symlinks /usr/local/bin/language to the relevant folder. 
Windows doesn't let you symlink without administrator privileges.  Fair enough, I figure, I'll just copy the binaries directly.  And that's where I'm at now: I'd like to copy these binaries into some equivalent of /usr/local/bin, somewhere user-accessible on the PATH.  But my knowledge of Windows isn't deep enough to know whether this is possible and my googling hasn't turned up anything either.  The PATH variable sharing a name with a fundamental filesystem feature kind of muddies searches up. 
Big thanks to anyone who can offer me a tip here.  

A:

There are several ways to set the PATH on Windows.  The easiest ones are explained in this SO answer. 

Add the path to My Computer->Properties->Advanced->Environment Variables->Path
Use set  PATH="%PATH%;C:\NewPath" setting the PATH for this session
Use setx PATH "%PATH%;C:\NewPath" setting the PATH for all sessions of this user in the future
Use setx /M PATH "%PATH%;C:\NewPath" setting the PATH for all sessions of all users machine-wide in the future
Modifiy the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment\Path and add C:\NewPath
Use the Environment. SetEnvironmentVariable .NET Windows Method to modify the registry key
Use PowerShell to modify it permanently

Disclaimer: I haven't tested which of these approaches require admin priviledges.