Microsoft introduced experimental languages on Azure Function App with runtime 1.x and that meant support for Python, TypeScript, PHP, Batch, Bash, and PowerShell. However, support for PHP, Batch, Bash, and Powershell was dropped with the release of runtime version 2.x. Of course this is the status as of today and I cannot guarantee if it stays the same.
If you also need to bring the support for one of these languages back, you should make sure your Function App runtime version is downgraded from 2.x to 1.x.
This is easily achievable. Simply open your Function App Settings and change the version using the portal just like below:
If you see FUNCTIONS_WORKER_RUNTIME with a value of dotnet under the App Settings, make sure you remove it completely from the list. Once this is all done, simply Restart your Function App and at least for now enjoy the use of experimental languages: