Qual é a diferença física entre os Hobbits e os Anões?

Anões e Hobbits têm origens muito diferentes são duas espécies diferentes

Anões são criações de Aule, o artesão.

in their beginning the Dwarves were made by Aulë in the darkness of Middle-earth; for so greatly did Aulë desire the coming of the Children, to have learners to whom he could teach his lore and his crafts, that he was unwilling to await the fulfilment of the designs of Ilúvatar. And Aulë made the Dwarves even as they still are

Hobbits eram um desdobramento de homens (provavelmente)

It is plain indeed that in spite of later estrangement Hobbits are relatives of ours [Men]: far nearer to us than Elves, or even than Dwarves. Of old they spoke the languages of Men, after their own fashion, and liked and disliked much the same things as Men did. But what exactly our relationship is can no longer be discovered.

Anões têm barba, a maioria dos Hobbits não

Not that I venture to disagree with Thorin, may his beard grow ever longer ...

... no Man nor Elf has ever seen a beardless Dwarf - unless he were shaven in mockery, and would then be more like to die of shame... For the Naugrim have beards from the beginning of their lives, male and female alike, nor indeed can their womenkind be discerned by those of other race, be it in feature or in gait or in voice, nor in any wise...

Hobbits eram conhecidos por serem incapazes de crescer barba

Anões falam Khûzdul e os Hobbits falam Westron

Anões têm uma linguagem secreta, que raramente ensinavam a outros e o próprio Tolkien não tinha realmente desenvolvido em nenhum de seus trabalhos publicados. Palavras como "Khazad-dum", "Zirakzigil" etc.

Outras diferenças

Existem outras diferenças entre anões e hobbits. Um dos principais é furtivo, Bilbo é trazido como um ladrão no Hobbit por causa de sua maior discrição em comparação com os Anões; Legolas também faz um comentário sobre o barulho que Gimli cria andando.

Há também um número relativo maior de hobbits femininos do que os anões femininos e, em vez de queixos cabeludos, os hobbits têm os pés peludos.

Já existe uma resposta excelente para essa pergunta por Edlothiad (não acho que alguma vez tenha conseguido responder a uma pergunta de Tolkien antes dele). Como a questão lista a linguagem como uma das coisas que os Hobbits e os Anões têm em comum, quero acrescentar um pouco sobre isso.

Hobbits

Os Hobbits adotaram o Westron quando migraram para o norte, para Bree e o Condado.

It was in these early days, doubtless, that the Hobbits learned their letters and began to write after the manner of the Dúnedain, who had in their turn long before learned the art from the Elves. And in those days also they forgot whatever languages they had used before, and spoke ever after the Common Speech, the Westron as it was named, that was current through all the lands of the kings from Arnor to Gondor, and about all the coasts of the Sea from Belfalas to Lune. Yet they kept a few words of their own, as well as their own names of months and days, and a great store of personal names out of the past.

_{The Lord of the Rings Prologue, Section 1: Concerning Hobbits
Page 4 (Single volume 50th Anniversary Edition)}

The Riders laughed. ‘It cannot be doubted that we witness the meeting of dear friends,’ said Théoden. ‘So these are the lost ones of your company, Gandalf? The days are fated to be filled with marvels. Already I have seen many since I left my house; and now here before my eyes stand yet another of the folk of legend. Are not these the Halflings, that some among us call the Holbytlan?’

‘Hobbits, if you please, lord,’ said Pippin.

‘Hobbits?’ said Théoden. ‘Your tongue is strangely changed; but the name sounds not unfitting so. Hobbits! No report that I have heard does justice to the truth.’

Merry bowed; and Pippin got up and bowed low. ‘You are gracious, lord; or I hope that I may so take your words,’ he said. ‘And here is another marvel! I have wandered in many lands, since I left my home, and never till now have I found people that knew any story concerning hobbits.’

‘My people came out of the North long ago,’ said Théoden. ‘But I will not deceive you: we know no tales about hobbits. All that is said among us is that far away, over many hills and rivers, live the halfling folk that dwell in holes in sand-dunes. But there are no legends of their deeds, for it is said that they do little, and avoid the sight of men, being able to vanish in a twinkling; and they can change their voices to resemble the piping of birds. But it seems that more could be said.’

_{The Lord of the Rings Book Three, Chapter 9: Flotsam and Jetsam
Page 557-8 (Houghton Mifflin Harcourt; Single Volume 50th Anniversary Edition)}

Anões

Os anões têm uma história muito mais longa e, enquanto usam o Westron para se comunicar com outras pessoas, eles têm sua própria linguagem que ainda usam entre si.

But in the Third Age close friendship still was found in many places between Men and Dwarves; and it was according to the nature of the Dwarves that, travelling and labouring and trading about the lands, as they did after the destruction of their ancient mansions, they should use the languages of Men among whom they dwelt. Yet in secret (a secret which unlike the Elves, they did not willingly unlock, even to their friends) they used their own strange tongue, changed little by the years; for it had become a tongue of lore rather than a cradle-speech, and they tended it and guarded it as a treasure of the past. Few of other race have succeeded in learning it. In this history it appears only in such place-names as Gimli revealed to his companions; and in the battle-cry which he uttered in the siege of the Hornburg. That at least was not secret, and had been heard on many a field since the world was young. Baruk Khazâd! Khazâd ai-mânu! ‘Axes of the Dwarves! The Dwarves are upon you!’

_{The Lord of the Rings Appendix F, Section I The Languages and Peoples of the Third Age
Page 1132-3 (Single volume 50th Anniversary Edition)}