As reference is made to the Hebrew alphabet in a couple of places on this site, a brief and incomplete note on its actual use in writing is provided here. Better references, of course, are available elsewhere for those wishing to pursue the subject further. This quick run-through may contain some inaccuracies, and is also inconsistent in its transliteration of Hebrew words. Note that Latin words are shown in bold to distinguish them from the Hebrew in italics.
Several of the letters of the Hebrew alphabet are the ancestors of vowels in our alphabet. Thus:
'Aleph: A Hé: E Vau: U (as well as V and W) Yod: I `Ayin: O
However, while vowels in the Latin and Greek alphabets had these letters as their ancestors, these letters represented consonants when they were used for writing Hebrew, and generally still do.
As Hebrew, like Arabic, is a Semitic language, the vowels within a word undergo considerable changes when the same word is used in the past tense, or as a gerund, and so on, including the vowels as full-fledged letters in the body of words is felt to actually slow, rather than enhance, the quick recognition of words in written text.
On the other hand, since Yiddish is a dialect of German, much as the Scottish dialect is a form of English, while it is also written with the letters of the Hebrew alphabet, in that case some of those letters do serve as vowels, this being congenial to German, as an Indo-European language, just as it is to English or Greek.
In modern Hebrew, and even in Hebrew as it was spoken at the time the Masoretic system of vowel pointing originated, the sounds of the vowel letters (such as the glottal stop for 'Aleph) had fallen into disuse, it is possible to write Hebrew, using its own alphabet rather than a Romanization, with vowels as full-fledged letters in a similar manner to how they are used for Yiddish. This is called scripta plena, and while it is not considered worthwhile for the normal writing of text, it can be used for providing a key to the pronounciation of words without having to resort to the use of the system of vowel points (which, of course, present difficulties in typesetting and so on).
The image at right shows many of the elements of Hebrew writing. It omits cantillation marks and Masoretic accents.
In the box on the left, the first (leftmost) column shows the letters and their names, along with their numerical values and final forms.
Several of the letters occupy two rows; in the second row, the name of the letter is not repeated, and usually a dot is added within the letter.
In the case of the letter Shin, however, there is a dot present above the letter in one of two positions. In the second position, Shin becomes Sin, representing an ordinary S sound like Samekh, rather than the Sh sound.
The dots within the letters Beth, Ghimel, Daleth, Kaph, Phe, and Taw thus shown are known as dagesh kal (in older grammars, as dagesh lene). They indicate that the actual sound of a consonant is changed to another value: from bh, gh, dh, kh, ph, and th respectively to the simple b, g, d, k, p, and t..
The second column shows dots in all of the letters except for Heth. However, the dotted forms of 'Aleph, `Ayin, and Resh are shown with boxes around them. This column describes dagesh hazak (in older grammars, known as dagesh forte). Here, the dot indicates that the letter is to be read as a doubled letter. The three letters shown with a box around them are not considered to be normally eligible to receive this mark, but are found with it in a few isolated instances in traditional editions of the Masoretic text of the Old Testament or Tanakh (Tanakh is a shortened compound of Torah, Nevi'im, u-Ketuvim, which means "The Law, the Prophets, and the Writings").
In the third column is shown yet another meaning that the dot within a letter may have. Here, the letters are shown wherein that dot is the mappiq, which indicates that the letter is to be sounded rather than remaining silent. Normally, it is only used within Hé and its use in the other letters shown in that column ('Aleph, Vau, and Yod) is rare.
In the fourth column are shown various items, most of which are oddities and rarities.
Across from 'Aleph, Hé, Lamed, Mem, and Taw, extra-wide forms of these letters (in the case of Mem, a wide form of final Mem) are shown. These were sometimes used to help in justifying lines of text.
Above the wide Lamed is shown the "broken Lamed". Instead of being used to make room for points above the letter, this is the form used when there is nothing to put there, as although the ascender on the letter does not reach as high in that case, it covers the whole width of the letter. So when points are placed above the letter, they are put above the portion of the conventional form of the letter not occupied by the ascender.
The normal form of `Ayin, when vowel points are not used, is shown in this column. Since the bottom of the letter is normally a large descender filling the width of the character, when vowel points are used, it is pushed up to leave room for them.
Across from Yod, we see final Yod with the Sh'wa within it. This vowel point indicates the absence of a vowel; it is usually omitted at the end of a word, but not in the case of Yod. Note that it is placed below the line at the top of the character, and therefore within the character, instead of below it.
Below the wide 'Aleph, we see a ligature for 'Aleph-Lamed, with a variant form below it.
Finally, also depicted are three very rare characters found in the traditional Hebrew text of the Old Testament: across vrom Vau, "broken Vau"; across from Nun, "backwards Nun", and across from Qoph, "joined Qoph".
And now, let us look at the chart in the upper right of the illustration, which shows the system of the vowels, at least as it is described in some old grammars. To show how the vowel points are related to the letter to which they are applied, each entry in the chart includes the letter Kaph as well as the vowel point applied to it.
The rightmost column in the chart shows the extra short vowels. There are only three of them:
The next column from the right shows the short vowels. These are:
The second column from the left shows the long vowels, at least as written when matres lectionis are not available. These are:
The leftmost column indicates how a long vowel may be indicated more explicitly by placing an Yod or Vau after the letter to which that vowel is applied, these additional letters being called the matres lectionis.
Qametz is the same symbol as Qametz Chatuph, and Chireq magnum and Chireq parvum are also the same. The distinction between these in reading depends on the consonant after the one to which the vowel is applied. Also, "long" and "short" do not refer to the usual changes in vowel quality these terms denote in English, but simply to duration; however, when vowel points are applied to modern Hebrew, Tzere and Cholem do indicate different vowel sounds, not simply different durations of the vowel sounds of Segol and Qametz Chatuph.
Finally, in the lower right of the diagram, we see three other symbols depicted, again each one applied to the letter Kaph.
We see Sh'wa, which we have already met in connection with final Yod, a mark indicating the absence of a vowel. This allows ambiguity to be avoided, for example, when Cholem is omitted, either because it is on the letter preceding a Shin with a Shin dot, or it is on a Shin with a Sin dot. However, Sh'wa is also used to indicate a very short E sound if it occurs inside a syllable instead of at the end of a syllable. The silent version is called Sh'wa Na, and the version that is sounded is called Sh'wa Nach.
The horizontal line above a letter is Rafé - this is used in some texts to indicate that a letter really doesn't have a dot inside it, neither a dagesh lene, a dagesh forte, nor a mappiq.
The third mark shown is Patach furtivum. This indicates a very short A sound that is forced by the presence of a guttural letter at the end of a word in order to make it pronounceable.