is pronounced differently by those Jewish people who, in the diaspora, settled in the regions of Ashkenaz (Genesis 10:3) and Sepharad (Obadiah 1:20). Sephardic Jews pronounced the letter 
The Festival of the Harvest
by Rav Michael Hattin
The following is an excellent examination of the counting period, and the link between agricultural and spiritual meanings of the festival by one of Israel's great rabbinic leaders. Excerpted and edited by JewishEyes.org where [square brackets] appear.
[… In this commentary,] we will consider the observance of Shavuot, here called the Festival of the First Fruits. Unique among the holidays spelled out in the Torah, the exact calendar date of Shavuot is not indicated, and instead it is calculated according to the date of Passover. The precise determination of the festival's date was the subject of great disagreement during the early days of the Second Temple period, and pitted the Rabbinic leadership of the people against opposing elements that rejected what they regarded as unwarranted 'tampering' with the plain meaning of the text of the Torah. In fact, the conflict between the Sages and the so-called Sadducees presaged many later battles between those who championed the existence of an Oral Tradition and those who demurred. It should be pointed out that according to ancient and well-founded traditions, the Revelation at Sinai, the Giving of the Torah to the people of Israel, took place on Shavuot.
The Dual Grain Offerings - The "Omer" and the Wheat Loaves
[…] The Passover observance is succeeded by an offering of an 'omer' of new grain, an amount equal to about 2.2 liters. This grain offering is significant, for it permits consumption of the new harvest, 'bread, roasted or fresh grain'.
The 'omer' offering ushers in a period of seven weeks that are to be assiduously counted one day at a time. The conclusion of the count, the fiftieth day, is also commemorated by an offering of new grain, this time in the form of two leavened loaves of wheat. Additionally, the day of the offering is celebrated as a festival that includes the by-now familiar prohibition of labor.
Taken together, it is clear that this post-Passover festival pivots around the agricultural event of the grain harvest. The even-week count begins with a grain offering and concludes with a wheat offering. The centrality of the harvest theme is emphasized by the parenthetical legislation concerning the 'ends of the field of the fallen stalks' that are to be left for the poor when the fields are cut. While the fiftieth day is linked in the text with the harvest of wheat, the grain associated with the initial offering of the 'omer' that begins the count is not specified. Awareness of the climate of the Land of Israel is helpful is deciphering the precise parameters, and sheds much light on the significance of the festival.
The Promise of Spring and Its Uncertainty
seem to be related to afaf 
(to strive eagerly for something). From avav we get the word eiv 
(a stalk which draws up nourishment from the soil). So R' Hirsch concludes that aviv 
means: “the time of completed stalk formation, the time of ripening grain”.Springtime in the land of Israel, occurring around March or April, is marked by the cessation of the northwestern storm winds that blow in from the Mediterranean Sea bearing cool temperatures and precipitation. As the rainy season draws to a close and the days begin to lengthen, the countryside literally comes to life, as the hills are covered by a short-lived blanket of green punctuated by vibrant bursts of wildflowers. Additionally, the fruit trees begin to blossom and the grain begins to ripen, in particularly the BARLEY. It is important to bear in mind, however, that while Spring days may be hot and dry, Winter winds and even rain can still make their appearance. In fact, the interplay between these two opposing climatic forces - the warm, arid winds of Spring and the cool, damp remains of Winter - can wreak havoc during the unstable interval that follows Passover, as the blossoming trees and maturing grains are particularly vulnerable to prolonged swings in temperature and moisture. This period of agricultural uncertainty continues until the Winter winds finally blow themselves out some weeks later.
In at least one place in the Torah, the season of the Spring is designated 'Aviv' precisely because it designates the season when the barley begins to mature. Recall that one of the final plagues to strike the land of Egypt was the hail. The sound of thunder, the sight of lightning and the downpour of hailstones must have been quite extraordinary in Egypt, where precipitation of any sort is highly unusual. Not surprisingly, it was not long after the plague of hail that the people left the land of Egypt, on the morrow of the first Passover. According to the Torah's description, the plague of hail not only filled the Egyptians with dread and wonder, but also left much devastation in its wake, for it destroyed the crops of flax and barley. The wheat and spelt, in contrast, were spared, only to be later ravaged by the plague of locusts that followed soon after. The text tells us why it was that the flax and barley were ruined, "for the barley was 'aviv' and the flax was in its stalks. But the wheat and spelt were not destroyed, for they ripen later…" (Shemot/Exodus 9:31-32).
In other words, because the barley and flax had already grown and their stalks had started to stiffen, they were much more vulnerable to being snapped and broken by the heavy weight of the hailstones. The immature wheat and spelt, in contrast, were flexible enough to bounce back after the hail had dissipated. Significantly for our purposes, the 'Aviv' of the Exodus, the time of the Spring, is here clearly associated with the BARLEY, "for the barley was 'aviv'…."
The Season of the Barley and the Pesach / Shavuot Link
Thus, Passover not only inaugurates the season of the Spring, it also introduces the beginning of the barley harvest, the 'aviv' of the Torah. This period continues for a number of weeks as the barley completely its growth and the fruit trees begin to bloom. While Biblical barley was typically used for animal feed, it is the wheat that constitutes the more important cereal. During the seven weeks that are counted after the offering of the barley, until the onset of the summer season, the fortunes of the wheat and the flowering trees are determined. If the coolness and wetness of the Winter incrementally decreases to be matched by a corresponding increase in warm, dry weather, then the grains and flowers will develop properly. If, however, the warm weather makes its appearance too early and is then followed by prolonged cold and and wet spells, the blossoms may open prematurely only to become damaged, while the grains may be blighted. It was only natural for the farmer of ancient times to expectantly count the days of this period of weeks until such a time as the dangers had passed, indicated in the fields by the successful ripening of the wheat.
The above agricultural analysis highlights a number of significant points. First of all, it indicates that the connection between Pesach and Shavuot is an intrinsic and organic one. These two festivals are not simply strung together by an artificial counting of weeks. Rather, they are integrally related through the process of the grains reaching maturation. Secondly, the Torah's injunction to 'count the weeks' is similarly not an arbitrary contrivance but rather an astute reading of the anxiousness of the season. Every day that uneventfully passes brings the grain crops one day closer to safely completing their development. No wonder that the binary nodes of the 'omer' and the wheat loaves, effectively delineating between themselves the duration of the Spring season, both function as enablers for the consumption of the new grain. It is as if the Torah implores us to recognize that the blessing of the new crops is solely the product of God's pivotal role in nurturing and sustaining them.
The Giving of the Torah and the Ripening of the Grains
Most importantly, though, the agricultural basis of the festival invites us to consider and reconsider its historical significance. It is well known, of course, that all of Israel's festivals are predicated upon a decisive duality: on the one had, they mark seasonal and agricultural cycles, and on the other hand they recall historical events. Thus Passover heralds the Spring and also commemorates the Exodus. Sukkot ushers in the Fall and also recalls the journey through the wilderness. In both of these cases, the link between the agricultural and the historical aspects is straightforward enough. The springtime of Passover, the coming to life of the vegetation after the long dormancy of Winter [15 Kislev - 15 Shevat], mirrors the birth of the Jewish people as they leave behind numbing slavery to finally breathe the fresh and invigorating air of freedom. The ingathering of Sukkot that inevitably exposes the farmer to long periods outdoors while he struggles to bring in his produce to settlement and safety indoors, parallels the perilous passage through the desolate wilderness in search of the Promised Land. What, however, might be the linkage between the ripening of the grain and the revolution at Sinai?
While often presented in the form of a truism, it is nevertheless the case that the Exodus from Egypt did not herald the complete emancipation of the people of Israel. Though physically freed from the bondage of the brick pits, the people were still very much held captive to the slave's way of life. For the slave, nothing is more real than the immediate, and nothing more significant than survival. The slave may yearn for 'freedom', but in his mind that freedom means only cessation from hard labor and nothing more. No higher ideals occupy his thoughts and no dreams of destiny inspire him. Once his physical bonds are loosened and he sheds the mire of mortar and clay that cakes his body, he considers himself 'free'. The precious discipline of self-mastery that sets apart true freedom from its garish and crude imitation is utterly beyond his ken.
The Exodus, however, was meant from the start to not only free a people from servitude in the most basic corporal sense, but to inspire that people don the more exalted mantle of ethical and spiritual development. Describing the outline of the Exodus process about to unfold, God said to Moshe that:
"…I will take you out of the suffering of Egypt, save you from their labor, redeem you with an outstretched arm and with great judgments. I SHALL TAKE YOU AS MY PEOPLE AND I SHALL BE YOUR GOD, AND YOU SHALL KNOW THAT I AM THE GOD WHO TOOK YOU OUT OF EGYPTIAN SERVITUDE…" (Shemot / Exodus 6:6-7).
In other words, the Exodus is to be but the first step along a long and arduous journey that will culminate in the people of Israel becoming God's people, understanding the true significance of their freedom, and using the freedom to choose the good.
The Challenges of Freedom
Not surprisingly, since the Exodus from Egypt introduced not only liberation from physical servitude but also a profound and spiritual transition towards more enlightened existence, it was accompanied and followed by great and difficult trials of faith and trust. Israel longed for freedom for the Egyptian taskmasters, but soon chafed under God's gentle demands to abandon the slave's circumscribed, egocentric, and morally insipid lifestyle.
Only at Sinai, as God presented the people of Israel with His liberating laws, was the potential of the Exodus truly unleashed. Forced to take another bold step of development, the people were charged to observe a way of life that aimed to elevate their physical freedom to a state of true liberation from the spiritual shackles that still held them in sway to Egypt and its blandishments. Of course, the Revelation was itself not the culmination of the journey, but it did introduce to the world the next and boldest step. To embrace the experience of Sinai is to choose moral, ethical and spiritual development as one's lifelong goal.
Understanding the nature of slavery and freedom, we are now in a better position to appreciate the agricultural aspect of this festival. Like the barley and wheat that gently sway in the fields at this time of year, Shavuot is about spiritual maturation and growth. Like the instability of the seven weeks and the anxiousness of the season, Shavuot is about the great struggles and sometimes setbacks that hound our halting steps toward spirituality. Like the transitional movement from Spring to Summer that is perfectly mirrored in the ripening of the grain, the 'counting of the omer' that so cohesively links Pesach and Shavuot describes in perfect miniature the awesome challenge that physical freedom presents. And like the dual offering of the barley and the wheat that the Torah enjoins during this time, Shavuot presents us with the promise and the privilege that Pharaoh could never extend: the opportunity to serve God.
No wonder that alone among the festivals, the calendar date of Shavuot is never spelled out explicitly in the Torah, for its connection to Pesach and to the process of the Exodus is its defining quality. The seven week interval between the two, the forty-nine expectant and promise laden days, highlights the profound truth that spiritual emancipation must begin where physical freedom is achieved. or else that freedom is but a shadow of itself. As the Festival of the Grain Harvest approaches, may we merit to internalize its liberating message.