This research was carried out by a group of experts from the CITiUS, Imaxin|Software, a Galician company and IXA NLP Group, from the Basque Country.
The team measured the quantitative distances of 44 European languages, allowing them to create the above graph, where each node represents a language and the edge represents the distance between the node on the node on the other side.
A extended review can be found in the Galician newspaper galiciaconfidencial.