Researchers have found that the world’s languages, despite their enormous diversity, are not free to vary in unlimited ways – a result that may also matter for the search for extraterrestrial intelligence. In a new study published in Nature Human Behaviour, an international team used Bayesian spatiophylogenetic analyses to test whether widely proposed grammatical universals persist once two major sources of similarity – shared ancestry and geographic contact – are taken into account. Their conclusion is striking: roughly one-third of 191 proposed universals are statistically supported, suggesting that some recurring grammatical patterns are robust features of human language rather than accidents of history. For SETI, this is important because it strengthens the idea that intelligent communication may not be completely unconstrained: even very different linguistic systems could converge on certain structural principles.

The researchers based their work on Grambank, a large database of grammatical features from languages around the world. The strongest support was found for universals involving word order and hierarchical structure, two areas central to how meaning is organized and transmitted. The models also suggest that language change is not random: over time, languages tend to move toward a limited set of preferred grammatical solutions. In a SETI context, this does not mean alien languages would look like human ones, but it does imply that complex communication systems may be shaped by shared cognitive and informational pressures. If intelligence elsewhere in the universe has evolved ways to encode meaning efficiently, some abstract organizational features – such as patterned hierarchy or stable relationships between elements – could be more likely to emerge.

The study does not argue that all traditional linguistic universals are real; in fact, most of the 191 proposals were not supported. Yet by identifying which constraints survive rigorous evolutionary testing, the authors offer a more precise picture of what may be fundamental in language. That makes the findings relevant beyond linguistics alone. For SETI researchers, the work provides a useful reminder that the search for intelligent signals may benefit not only from astronomy and engineering, but also from understanding which features of communication are most likely to endure across radically different conditions. If there are deep constraints on grammar, they may help us imagine what an intelligible non-human signal could look like.

For more details, read the full article by Nature Human Behaviour.