Minecraft defaults to English (US) when the language field in options.txt is missing

During the first boot or when the language field in options.txt is missing, Minecraft  defaults to English (US) instead of system language. For comparison Minecraft Launcher and Minecraft: Bedrock Editon will use system language if their settings are missing.
Steps to reproduce:

• Set your system language to be anything other than English (US).
• Delete the options.txt file in your Minecraft instance folder or set the lang parameter in it to nothing.
• Notice that Minecraft will use English (US) instead of your system language.