Dependency length minimization: Puzzles and Promises
This is an incremental critique for linguists and researchers in language processing, highlighting potential validity issues in cross-linguistic studies.
The paper critiques a prior study on Dependency Length Minimization (DLM) across 37 languages, pointing out overstatements, methodological flaws like ignoring genre uniformity and using a projective baseline, and hasty conclusions without statistical evidence.
In the recent issue of PNAS, Futrell et al. claims that their study of 37 languages gives the first large scale cross-language evidence for Dependency Length Minimization, which is an overstatement that ignores similar previous researches. In addition,this study seems to pay no attention to factors like the uniformity of genres,which weakens the validity of the argument that DLM is universal. Another problem is that this study sets the baseline random language as projective, which fails to truly uncover the difference between natural language and random language, since projectivity is an important feature of many natural languages. Finally, the paper contends an "apparent relationship between head finality and dependency length" despite the lack of an explicit statistical comparison, which renders this conclusion rather hasty and improper.