Owing to the fact that this is the only known suggestion as to the history of the Yoakum name, I have included it for informational purposes only. This is only one of many possible histories we can construct of the origin of the name, and is likely to be only the first of many potential scenarios.
DISCLAIMER
"Thus my dedication to this genealogy is heartfelt and in bitter protest against the tendency of so many Americans to forget their heritage."
~H.C. Smith
Information on this and following pages is from the book
"Jachim, Joachim, Jochems, Yoakum, Yocom, Yocum, Yokum And Allied Families" by H.C. Smith.
Copyright 1963, Ca., U.S.A.
"OUR ANCESTORS, Page XII
In genealogy as in every other subject of interest and importance to mankind there is a happy mean between two extremes...For example, the Chinese worship ancestors to a degree that they let much arable land go unculticated because some remote ancestors have been buried under it; while, conversely, many an American is so disinterested that he does not know the maiden name of his mother. Also, there is the man that is so proud of his ancestry that he feels it totally unnecessary to accomplish anything of importance himself; while another of standing and accomplishment in his community is so self-sufficient that he fears to have his ancestry traced lest somewhere back in the line will be found one who was "hanged as a horse thief." This quoted phrase is one all too frequently directed at the genealogist attempting to clear up a family line.
The "self-made man" idea has so taken hold of many Americans that they invariably reply to queries as to ancestors with "It is not what your ancestors were or did but what you are and do that counts." While this is true it is much more likely to be so if the individual knows that he has an honorable ancestry to perpetuate. Ancestors are the necessary concomitant of the existence of every individual. (concomitant means: companion)
"Not to know what happened before we were born is to remain always a child; for what were the life of man did we not combine present events with the recollections of past ages?" (Cicero) Someone has aptly said: "It is only a mule that has no pride of ancestry, nor hope of posterity."
<(deleted paragraph..H.C.digressed into a parallel train of though, relaying information about Abraham Lincoln and his dubious ancestry, etc.)>
Delving into the history of American families discloses a very consistent pattern: the noble and ignoble, the intelligent and the unintelligent, the provident and the improvident, the stable and the unstable, the rich and the poor-and this applies to our own lines as to the lines of others. In consequence, our genealogical search is for no other purpose then to establish an honest and as complete as possible history of the family. Like most families ours can boast a maximum of honor and a minimum of dishonor.
In searching genealogical lines, family given-names are of significance. It is a very meek and colorless woman that does not have considerable to say about the naming of her children, and having family pride, insists on naming some of the children after certain of her own beloved or prominent forbears. On the other hand, because of the old law of primogeniture, and the assuming of the family surname of the man by the woman at marriage, both usually feel pride in perpetuating the given-names of the males and females of the husband's line. Thus, while family groups of the same line vary widely in their so-called Christian cognomens, these still are indicative as to the origin of the group.
Tne stumbling block in the way of disentangling the various families of a line of early Americans was their tendency in the selection of Christian names to try to first exhaust the Old Testement, then add a few names from the New-the size of families giving them rather free play along this line.Again, aside from the fact that there was no lexicon that was a standard for the spelling of any words, much less names, many of the early official license clerks, ministers and patrons lacking even a rudimentary education, became the world's champion original spellers. *
* the lexicon H.C. Smith referred to is a standard dictionary. In the U.S. , the first appearance of a standardized method of spelling didn't occur until the early 20th century.Also of note is the fact that just because the standard dictionary was printed does not mean that it was in common use, especially in rural areas.
PRONUNCIATION OF NAMES, page XIII
   As the letter "J" was the latest addition to our alphabet, and in foeign language, where existing, is used interchangeably with the letter "I", it makes our pronunciation of words containing this letter very difficult for them to grasp.
  The name John is the most frequently given Christian name in America and much used in man other countries. For example, in Scotland it is spelled Ian and pronounced Yahn; in Russian; Ivan and pronounced Eevan; in the Balkans Jan and pronounced Yahn; in France, Jean and pronounced Zhon, in Germany Johan(n) and pronounced Yohan; in spain Juan and pronounced Hwan, etc. etc.
ORIGIN OF THE YOAKUM YOCOM,YOCUM PATRONYMIC
   The original Iagum, Iugum and Jagum stamp the name as of Celtic origin.
   One article that I read, but failed to preserve, gave the Celts as a tribe of Hebrews who settled in an area north of the Caspian Sea; but modern philogogists are content to begin their history with the Gauls, who settled in France. A very complete discussion of that race may be found in the older editions of the Encyclopedia Britannica. (H.C. wrote this before 1963)
  The harshness of their language is retained to a greater or lesser degree in the speech of the Scot and, especially, of that of the natives of Wales. In fact, Wales seems to have been settled by Walloons from upper Belgium, who were termed Welsh by the Germans and Walshe by the Latin nations. In all probability, this accounts for the tradition of Welsch descent passed on to his descendents by Valentine Yoakum and given by Professor Henderson Yoakum, author of a History of Texas, and contributed to Vol. 2 of The Tennessee Records and recorded by Acklen.
  The Celts of southern Belgium were, in the main, Protestants. After the revocation of the Edict of Nantes and the persecutions that followed, these Celts fled, many into the Lower Palatinate in Germany, but a goodly number went on into Holland and Scandinavia.
  Those inclined toward the military, into Denmark and Sweden;those inclined toward the life of mainers sought localities in Friesland and coastal points.    One tribe was called Picts because of their dexterity in handling the pique, a spear like weapon.
   England, Ireland, Scotland and Wales, all had heavy early settlements of Celts.
  Undoubtedly, some of the descendents of Yokim were among the Lost Tribes of Israel in their peregrinations. Of necessity, they must have intermingled with the primitive tribes, as well as with every people capable of expressing itself by way of language. This influence would account for the uncouth names of Iagum and Jagum, and the, to us, complicated names of the Dutch immigrant settlers of New Amsterdam (now New York City) These examples are mentioned by Guy D. Yoakum in the second article of the introductory history of his line. He had made extensive research, which stemmed from the New York area.
   Like Dr. Charles A. Yocom, the early research labors of this compiler stemmed from the Philadelphia area. This was the area chosen by the men sent by King Gustavus Alsophus of Norway and Sweden to establish a Scandanavian Colony in America. Moses and Peter Joccom were among the men who came.
Since, in all of the languages involved, the letter "J" was pronounced the same as an English "Y", Moses and Peter Joccom (Joccum) were anglicized to Moses and Peter Yocom or Yocum.
  Likewise, the Dutch immigrants, Jochems and Jochemssen, were anglicized to Yochems and Yochems'son.  The Holland Dutch immigrants to Philadelphia in 1763, in "Oaths of Allegiance of Foreigners arriving on the ship "Harle" of London", Captain Ralph Harle, from Rotterdam, qualified Andreas Yokem, age 40 and Michael Yokem, age 33.(Archives of Penna., 2nd Edition, Vol. 17, p. 123.)
   This helps us to evaluate the quotations from the Media Research Bureau's output on The Name and Family of Yocum, which follow:
  "The name of Yoakum is believed to be an Americanization of the German baptismal or personal name of  Joachim.-----Early seated in Germany, Silesia, Zealand, Sweden, Alsace and other parts of continental Europe, the Joachim family, from which the Yocums of America are believed to be descended, belonged, for the most part at least, to the landed classes. The German family of Joachim of Joachimsburg, an ancient and honorable line, were represented in the year 1747 by Johann Ignace Joachim, an officer in the German army; while the Jocham of Jochamsburg family of Alsalce were represented in 1754 by Johann Ignace Jocham, who was one of the Knights of the Holy Roman Empire.  However the records of these lines are only fragmentary.
   It is probable that the first of the name in America were of comparatively humble origins and that they were of that large group of German immigrants who adopted their surnames after or when coming to this country. ------they had much in common only the fact that their progenitors bore the Christian name of Joachim. However, this is purely conjecture, since the ancestry of the immigrants of that name has not been established."
To those who are inclined to consider it necessary to present Armorial Bearings to their friends and descendants, the Bureau presents:
"The coat of arms borned by the ancient German family of Joachim--is described as follows: (Rienstap, Armorial General, 1884):
Arms:  "quarterly: 1 and 4 gules a lion or the lion of the first quarter contourne; 2 and 3, azure a coronet, or, somme three ostrich plumes argent.
Crest: "The furnishings of the second quarter."
Lambrequins: "Dexter, or gules, the sinister argent and azure."
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Information on this and following pages is from the book
"Jachim, Joachim, Jochems, Yoakum, Yocom, Yocum, Yokum And Allied Families" by H.C. Smith.
Copyright 1963, Ca., U.S.A.