Ok, Interior Design is closely associated with interior decoration, you act simply on the surface of the inner space (eg. appartment, hall area..etc), the max. thing you can do is add a partition or remove a non-structural wall (sometimes u can add some sort of stairs but not heavy duty ones).
However, with Interior Architecture, aside from the structural columns and the building extertior and foundations, the whole space is yours to design; I.e. you can add floors, levels, walls weather straignt, inclined (has to be structurely approved though 1st), stairs, elevators (if u have enough space for that)...and the list goes on..that's plus the work of the Interior designer as well.
To sum up, Interior Architecture is more deep into structure and architecture than Interior Design.
at all most the same for me
interior architect reform the interior environment ( walls ,spaces size , function , structural and so
interior design they can do the same with some little knowledge plus they have better
sight for interior spaces because architect work always with large scale elements
the interior work with entire interior space and reform it from start to finish
designing,Planing,reform walls ans spaces, analysis,functionality,furniture , and finishing materials,...etc