The first question is--if I understand what you're proposing--(relatively) easy. The second is much harder, perhaps impossible. The reason the first question

The first question is--if I understand what you're proposing--(relatively) easy. The second is much harder, perhaps impossible. The reason the first question is relatively easy is because of syntax (sentence order, but also the order of words in phrases). If it's a real language, that order is not random; the English word "the" shows up before "man" much more often than it does before "listens", and so for other words. This is true even in so-called free word order languages, which are really free phrase order languages. The other thing that could make the first question relatively easy is morphology. If you've decided to make a language that has inflectional morphology (in English, suffixes like -ed and -ing), that also helps determine whether the language is "real", because in a real language not all words will take the same affixes--you can't say 'theseing' (these-ing) in English. In other words, the affixes that you find on a given word are not random. Of course if you decide not to give your language inflectional morphology, this won't help--but if you do that, then your language's syntax will have to be more rigid: in a language with case marking affixes, like Latin, you don't need word order to tell which noun is subject and which (if any) is object; but you need a more or less fixed word order in English, because (apart from pronouns) we don't have any case marking.