From various sources, we learn about those short people:
They are older than thought:
“These new findings suggest that Homo floresiensis is indeed a dwarfed form of Homo erectus from Java, a small group of which must have gotten marooned on Flores and evolved in isolation,” van den Bergh says.
The fossils also dispel any lingering theories that the hobbits were a form of diseased Homo sapiens, with smaller heads and statures due to developmental conditions such as Down syndrome or microcephaly, the birth defect linked to the modern Zika outbreak. (NatGeo)
They are said to have shrunk rapidly:
Scientists have discovered the 700,000-year-old ancestor of the tiny primitive human known as “the Hobbit”.
Its fossils indicate that the normal-sized primitive humans who first set foot on the Indonesian island of Flores shrank “rapidly” to become Hobbit-sized (BBC)
Found after a ten-year hunt, their ancestry is still uncertain:
The hobbit’s discovery in 2003 in Liang Bua cave, by a team led by the late Australia-based rock-art specialist Mike Morwood, was an instant sensation. But its place in the human family tree is contentious. Morwood’s team proposed that it was a shrunken Homo erectus, the same species that probably evolved into Homo sapiens in Africa and that roamed as far as Europe and Asia. Other scientists who have examined features of H. floresiensis, such as its long, flat feet, think that it descended from a smaller, more primitive human relative such as Homo habilis or even Australopithecus, known only from remains in sub-Saharan Africa.(Nature)
“There is still no ancestor-descendant sequence from Flores that supports body size reduction from a larger bodied H. erectus ancestor,” says Peter Brown at the University of New England in Armidale, Australia, who led the original hobbit excavations at Liang Bua.
But dramatic reduction in body and brain size could, in principle, have happened in such a short time, says Stephen Montgomery at the University of Cambridge, UK, who has studied evolutionary dwarfism in other primates. “The rate of change to dwarf an erectus in [a few hundred thousand years] would probably not make me choke on my cereal,” he says.
From The Scientist:
The findings open up new questions about how these hobbit-like hominins first reached Flores. Van den Bergh said he thinks the most likely explanation is that a tsunami stranded H. floresiensis’s ancestors on the island, where evolutionary pressures eventually shrunk their brains and bodies.
However, “we’ve so far only discovered a small number of fossils from Mata Menge,” van den Bergh noted. “More questions must await the discovery of additional fossil remains.”
Yes. Wait till they dig up the ancient laptop … 
See also: The Little Lady of Flores spoke from the grave. But said what, exactly?
Follow UD News at Twitter!