When is a computer language called machine dependent?

When the code is targeted towards a specific machine architecture. Machine code is entirely machine-dependent, as is the low-level assembly language used to produce that machine code. High-level languages are not machine dependant, however source code can still be targeted towards a specific architecture or platform. Such code is non-portable, however many high-level languages provide methods to filter machine-dependant or platform-dependant code such that the same source code can be compiled on different machines and platforms.