Manejarse

Manejarse
 

I just heard No me manejo en el idioma and took it to mean "I don't handle myself well in the language" or something similar. Is that a common use of manejarse?

I might prefer "desenvolverse" for this case, but yes, it is a common use of "manejarse".

No me manejo con el idioma. No me manejo bien en inglés.

From "manejarse" (like when you have your cast removed and you still need some rehabilitation but you manage around pretty well) and "manejárselas" (-las as a pronombre lexicalizado- to get by or along in a variety of situations). They are pretty colloquial.

In Spain we say desenvolverse o arreglarselas.