First of all, some of the readers of JRRT may know that none of the Hobbits in the original Westron (Shire dialect or not) is named what he's named in the pages of Lord of the Rings. Adûnaic is a language that to us would sound Oriental, and Westron is descended from it.
Tolkien has himself sufficiently analysed Samwise and Hamfast as "halfwit" and "stay-at-home" and some may recall that Frodo is - I would say a comprommise between the Latin and Danish forms of - Frotho or Frode, a king of Denmark or two kings of Denmark, the single or the second of which lived in the time of Caesar Augustus, the single or first of which hosted the grand-step-son of Odin and found out he was no god.
But what about Fredegar / Fatty, Peregrin / Pippin, Meriadoc / Merry?
If Frotho is a name from Gesta Danorum by Saxo Grammaticus and Frode from its Danish translation, there is also a Gesta Francorum, an older book, of which the main author is St. Gregory of Tours, but which continues into the times past where he left off, and that written by Fredegar of Tours. I am not sure whether Fredegar is a learned construct or a saint, but that is where Fredegar comes from. Fatty obviously needs no explanation, after he had been in certain dungeons, with lean diet, "Fatty no more" ...
Pippin is also a nearly self explanatory word, it is English for Apple-Seed, and perhaps Pippin is named like Sam Gamgee is acting somewhat in the vein of Johnny Appleseed. And his taste for beer matches Johnny Appleseed's affinity for cider and applejock. But what about Peregrin? There is a St. Peregrino Laziosi who was a cancer patient, is patron saint of cancer patients, and is probably the most known Servite Saint after the Seven Founders (most famous of whom is St. Alexius Falconieri). As St. Peregrine was healed from a cancer or infection in the leg just the last night before a leg amputation, he lived on to 85. Some learned men have said that that is a very fabulous age for the Middle Ages (though St. Alessio died at 109 or 110 years, born in 1200 and died in February 1310).
St. Merri or older spelling Merry is in Latin Meredicus - he was a hermit and abbot who died on Aug. 29th (decapitation of St. John) in AD 700. Obviously, as Tolkien points out, Merry was chosen as nickname because of the meaning "merry" but this doesn't preclude that he had seen or heard of the saint. If he found his distaste for the French by a hit-and-run car accident in Paris, he would probably have been able to see the Church of Saint-Merri.
Despite the fact Merry is used as nickname for Meriadoc, this is not a version of Medericus. A king and a saint are involved:
Conan Meriadoc, semi-mythical king of Brittany in Gaul
Meriasek, Breton saint, patron of Camborne
as the wiki said./HGL
PS : Happy Hobbit Day, Tolkien Fans!