There's a lot more to learning a different language than learning substitutions.
For starters, there is hardly any bijective mapping between words. Translating 'run' to German could mean any of 'rennen, renne, rennst, rennt, renn, laufen, laeuft' and I am sure I am missing quite a bit.
And that only scratches the surface, let's not get started about Grammar or idioms, etc.
The word order really only adds negligible overhead.
You get closer to something bijective when you only consider lemmas, but then you'll probably have around 1/3 that are bijective, 1/3 that 1->2 or 3 and 1/3 that are 2 or 3->1.
For starters, there is hardly any bijective mapping between words. Translating 'run' to German could mean any of 'rennen, renne, rennst, rennt, renn, laufen, laeuft' and I am sure I am missing quite a bit.
And that only scratches the surface, let's not get started about Grammar or idioms, etc.
The word order really only adds negligible overhead.