Identifying function words

[Emma May Smith]

I remember in university working on a project with Jana, who spoke Czech, and Gabija, who spoke Lithuanian. One of my tasks was the go through the written report (in English) and check that the definite and indefinite articles (the, a, an) were in the right places, because neither of their languages had them. Even though they both knew English, articles were basically something pretty alien to their way of thinking about language, despite being bleedingly obvious to me. Both Czech and Lithuanian are, of course, Indo-European.

So while function words have the potential to be easily identified, we can't be sure which of them exist. Indeed, from the list you provide, none are truly universal as separate words.