These are very, very, very rough ideas of what a grammar for this language may look like, they're open to suggestions. Crafting the grammar (at least for a non-linguist like me) is definitely the hardest part of designing such an auxiliary language, followed perhaps by defining a simple enough phonology that will not compromise their recognizability.
- grammatical relationships are represented in strictly analytic fashion => use prepositions
- "concept-building" morphology, instead, can be agglutinating (and, just a little maybe, synthetic) but very simple and always about concatenation
- no articles
- no possessive pronouns/adjectives ("tu mi" = "mine, to me, for me", tumitelefon = my telephone)
- any noun can also be used as a verb and viceversa (like in English but taken to the extreme)
- optional verb marker for extra clarity (auxiliary verb "du", special case of the importing from Enlish rule, if any better alterantive to "du" is found it can be changed)
- strict SVO order all the time
- adjectives are always PREmodifiers (like most of English, German, Hindi...)
- premodifiers can be stringed up together with the noun (like some infamous examples in German)
- zero-copula whenever possible (the verb "to be" is not that important)
- PREpositions, not postpositions
- nominative/accusative only through word order
- dative possessive (and genitive) with "tu" preposition, meaning "to" (again special case of importing from English)
- logical subject is always grammatical subject
- every inanimate verb argument is accusative (dunno how to express it???) for example: not "listening TO something" but *"listening something"
- no passive diathesis (passive voice) as a consequence of another rule.