You might think they are all different at a superficial glance. However there are linguistic universals, which are shared by large quantities of languages, and larger still are the similarities when you take away word-order and whether something is an adposition or an affix.
So it is quite easy to use the most common and regular grammar, which was most likely spoken by mitochondrial Eve near the great lakes of Africa. Post-positional SOV is the kind of grammar we are so innately attuned to, that deaf people, never having heard spoken language develop it all on their own (https://en.wikipedia.org/wiki/Al-Sayyid_Bedouin_Sign_Language ). Even people that speak an SVO language natively do better with a new SOV language vs an SVO one http://langcog.stanford.edu/papers/TFJ-cogsci2011.pdf
Anyways, I don’t expect many people to learn a new language, that why the ideal grammar is mostly reserved for the core-language or interlingua which is also the bytecode. Instead there are formal variants of human languages which share vocabulary and word order of the native language — even though they are more regular and have a more limited dictionary.