Fascinating. Among other things – it’s probably no coincidence that, in several I-E languages (e.g., Latin and Greek),* -a* can be “feminine singular” or “neuter plural.” The neuter plural (e.g., data, plural of datum) is an abstract noun* from a verb (“to give”), conceived as a collection – so, the modern English tendency to consider “data” as singular is sort of going back to its roots.
*As were “feminine singulars,” at first – as thy still are in, say, Spanish (gloria=glory; muerte=death; gente=people…)