Many New Testament scholars look at language typology with suspicion. Some believe that using typological studies is dangerous because they have the potential to mislead the scholar to draw conclusions about Greek grammar not from the internal structure of the language, but instead the structure of other languages. I would like to suggest that is not true. In fact, I would like to suggest that the complete reverse is true.

Make no mistake, there is always a danger of a scholar (generally unintentionally) making the language they’re studying look more like or less like other languages. But this is a danger that is completely separate from typological research. In fact, I would suggest that the danger being realized is more likely when someone is exposed to one or two languages rather than when one is exposed to many languages. For the English speaker who is studying Ancient Greek grammar, that person is going to either be inclined to make Greek more like English or less like English either consciously or unconsciously. Its going to happen. If anything, being familiar with what a broader set of  languages do is only going to function as a safe guard against these two inclinations rather than making it more likely.

It wasn’t typological study that led A. T. Robertson in Grammar of the Greek New Testament in Light of the Historical Research to put forward an eight case system for Koine Greek. No, it was instead the study of a single language: Sanskrit.

It wasn’t typological study of language that led the grammarians of the centuries before Moulton, Blass, & Robertson and the 19th century comparative grammarians to provide a primarily tense-based description of the Greek verbal system. No, rather it was those grammarian’s knowledge of their native tongues and the language of the academy that caused it: Latin, English, German…

Source: koine-greek.com