Free The Peoples of Middle-earth by J. R. R. Tolkien Page B

Hobbits were a people more nearly akin to Men than any other of the speaking-folk of the ancient world, it might be supposed that they would possess a language of their own, different from the languages of Men but not unlike them.
    Yet of this there is no evidence in any record or tradition.
    Admittedly none of the legends of the Hobbits refer to times earlier than some centuries after the beginning of the Third Age, while their actual records did not begin until after the western Hobbits had settled down, somewhere about Third Age 1300; but it remains remarkable that all such traditions assume that the only language spoken by Hobbits of any kind was the Westron or Common Speech. They had, of course, many words and usages peculiar to themselves, but the same could be said of any other folk that used the Common Speech as a native tongue.
    [The latter part of this paragraph, following any record or tradition, was rewritten thus: They had, of course, many words and usages peculiar to themselves, but the same could be said of any other folk that used the Westron as a native tongue. It is true that none of the legends of Hobbits refer to times earlier than some centuries after the beginning of the Third Age, while their actual records did not begin until after the western Hobbits had settled down, somewhere about Third Age 1300, and had then long adopted the Common Speech. Yet it remains remarkable that in all such traditions, if any tongue other than the Common Speech is mentioned, it is assumed that Hobbits spoke the language of Men among whom, or near whom, they dwelt.]
    $22. Among Hobbits [added: now] there are two opinions.
    Some hold that originally they had a language peculiar to themselves. Others assert that from the beginning they spoke a Mannish tongue [> Mannish tongues], being in fact a branch of the race of Men. But in any case it is agreed that after migration to Eriador they soon adopted the Westron under the influence of the Dunedain of the North-kingdom. The first opinion is now favoured by Hobbits [> is favoured by many Hobbits], because of their growing distaste for Men," but there is in fact no trace to be discovered of any special Hobbit-language in antiquity.
    The second opinion is clearly the right one, and is held by those of most linguistic learning. Investigation not only of surviving Hobbit-lore but of the far more considerable records of Gondor supports it. All such enquiries show that before their crossing of the Mountains the Hobbits spoke the same language as Men in the higher vales of the Anduin, roughly between the Carrock and the Gladden Fields.+ (11)
    $23. Now that language was nearly the same as the language of the ancestors of the Rohirrim; and it was also allied, as has been said above, both to the languages of Men further north and east (as in Dale and Esgaroth), and to those further south from which the Westron itself was derived. It is thus possible to understand the rapidity with which evidently the Hobbits adopted the Common Speech as soon as they crossed into Eriador, where it had long been current. In this way, too, is explained the occurrence among the western and settled Hobbits of many peculiar words not found in the Common Speech but found in the tongues of Rohan and of Dale.++(12) (* Supported, as it appears to them to be, by the fact that among themselves they speak now a private language, though this is probably only a descendant, the last to survive, of the old Common Speech.) (+ [The following footnote was added: Though the Stoors, especially the southern branch that long dwelt in the valley of the Loudwater, by Tharbad and on the borders of Dunland, appear to have acquired a language akin to Dunlandish, before they came north and adopted in their turn the Common Speech.])
    (++ In Gandalf's view the people of 'Gollum' or Smeagol were of hobbit-kind. If so, their habits and dwelling-places mark them as Stoors. Yet it is plain that they spoke [> as Stoors; though they appear to