I'm still learning how to create homebrew classes and am currently stuck trying to figure out how to get a class feature to unlock additional options, in particular, language options as the class progresses in levels. 

Essentially the class feature has it's main feature that becomes available at 3rd level. This class feature also allows the character to learn an additional language at 3rd, 11th and 17th level. The problem I'm having is in regards to adding the drop down menus to allow the player to select their additional languages at the right levels. I've managed to add one that does appear at 3rd level and works as intended but can't get additional ones to appear for 11th or 17th level. On top of this my current attempts to fix this issue have only resulted in blank class option menus appearing in the class feature box.

Any suggestions on how the fix this and get the feature working as intended would be greatly appreciated.

Modifier: Language -- Choose a language.

Yep, done that. Which is how I've got the first one but I need to get two more and at the appropriate levels. As far as I can tell just adding another language modifier will cause it to appear at 3rd level as well, instead of 11th and 17th as intended.

Just create 3 class features all adding the language/chooose a language modifier and have these class features have different "required level"s.

Was hoping to avoid that but if it's the only way, it's the only way. Thanks